A Penny Doubled Everyday
July 10th, 2006 by Alan YuA few years back I was having a conversation with some people on how whenever you decide to invest in something for the long term, you should always think ahead on what would be the best choice in the long run while having persistence to follow through with it. The scenario was that if you were given a choice to receive one million dollars in one month or a penny doubled every day for 30 days, which one would you choose? When I first heard this, I knew that the penny doubled everyday must have been the better choice to go with as it was a little obvious to me that it had to be a trick question of some sort. But how much better would it be was not something that I knew immediately. So to demonstrate this, it was actually written out with all the calculations and it turned out to something like this:
Day 1: $.01
Day 2: $.02
Day 3: $.04
Day 4: $.08
Day 5: $.16
Day 6: $.32
Day 7: $.64
Day 8: $1.28
Day 9: $2.56
Day 10: $5.12
Day 11: $10.24
Day 12: $20.48
Day 13: $40.96
Day 14: $81.92
Day 15: $163.84
Day 16: $327.68
Day 17: $655.36
Day 18: $1,310.72
Day 19: $2,621.44
Day 20: $5,242.88
Day 21: $10,485.76
Day 22: $20,971.52
Day 23: $41,943.04
Day 24: $83,886.08
Day 25: $167,772.16
Day 26: $335,544.32
Day 27: $671,088.64
Day 28: $1,342,177.28
Day 29: $2,684,354.56
Day 30: $5,368,709.12
Quite a big difference once you look at it as you would be getting over 5 million dollars with the penny doubled everyday for 30 days route. The funny thing when I look at this is how it is almost like starting a business and trying to make a profit. In the beginning you struggle a lot to get things going and afterwards once it reaches to a point it just takes off smoothly. How does that analogy go again……it is something like starting a business is like a rocket ship taking off into space. You spend 80% of your fuel during take off and once it reaches a certain point it flies smoothly with minimal consumption.
March 3rd, 2007 at 8:11 pm
thank you for sharing that in the internet.
April 19th, 2007 at 4:05 pm
This was a wonderful lesson. I was thinking just like Mr. Alan Yu. I went with the penny doubled everyday. When I seen just this actually visualized. What a remarkable difference.
I enjoy reading lessons like these. You can become more insightful.
Thank you
Audre Chaney
April 20th, 2007 at 6:43 am
Well, if the question was “Would you rather have a million dollars, or a penny doubled every day for 27 days,” the lesson wouldn’t really be there, would it?
Don’t be afraid to challenge your assumption…because eventually, somebody else will.
May 9th, 2007 at 8:59 pm
actually joewatch the lesson would still be there. because the 5+ million dollars is just day 30. Now you have to add all 30 day together. so even at day 27 you should have in excess of 1 million dollars.
at the end of 30 days when you add the sum of all 30 days you have over 12 million dollars.
May 18th, 2007 at 5:25 am
On the “start with a penny and double every day for 30 days
= $ 10,737,418.24″
By my calculation (2) raised to the 29th power is
1,073,741,823.00 which a factor 100 times greater than your answer .
May 18th, 2007 at 10:11 pm
Wow, this is starting to feel like a math class for what was intended to be more of a expanding one’s way of thinking type of post.
But in general, $10,737,418.24 would be the 31st day if you were using the penny route. My guess is that your calculation was based on the fact that you first went .01 cent multiplied by 2 which equals .02 and you considered that as day one when really the first day should be just the one penny.
Similar to your next example, it seems like you went 2 multiplied by two which equals 4 and you considered that as day one when the first day should be the two by itself. Otherwise your 29 day calculation is really using thirty days for that example.
Just to note, the number I came up with in your example would be 1,073,741,824.00 with the way you calculated it and I’m not really sure what you are exactly implying with the 100 times greater statement as if you are multiplying it by “2″ you are basically trying to say “Two dollars doubled every day” which of course would be a lot greater in value. For 29 days to get similar results you would have to calculate it as “.02″ doubled for 29 days.
December 3rd, 2007 at 7:14 pm
The original information is correct, all comments are wrong. My dad needed this answer for a test in his job an there was NO answer over 5.5 million. BTW: His answer was right.
December 3rd, 2007 at 7:16 pm
well, not ALL comments are wrong:)
December 30th, 2007 at 11:35 am
What everyone has forgotten is if you start with a penny and the next day you double it at 2 pennies, well you actually have a total of 3 pennies…..so at the end of the 30 days make sure you add up all the numbers. This would be about double of what your final day number is.
January 9th, 2008 at 3:45 am
No the $ 5.4 million (approx.) should be the final result, as double your money means that yesterday’s sum is already included in today’s amount.
January 24th, 2008 at 5:21 pm
Ok, not to harp on about this, but if you use the power method, what exactly would you do to get the right answer?
would it be .02 raised to the 28th power? What is the equation for this?
January 29th, 2008 at 5:29 am
It is a simple question with a simple answer. Why do you make something out of it that it is not?
February 21st, 2008 at 6:07 pm
Just to let you know that on Day 24, you have entered $83,386.08, when in fact it should be $83,886.08, but the amount on Day 25 and all others are correct. Just a typo error when entering the amount.
February 21st, 2008 at 6:42 pm
Good eye there Deb. I’ve made the change. Thanks.
March 18th, 2008 at 6:19 pm
What is the darn equation for the love of god tell me!!!!!
March 24th, 2008 at 6:24 pm
So.
Any ideas on how to actually apply this?
It’s one thing to double one penny to two (”Oh, look. There’s a penny on the floor. I just made it to step two.”). But how on earth would you keep this up consistently for 30 days straight. That’s one month. One million in one Month?!
April 18th, 2008 at 7:31 am
Adjust your income for taxes and see how things work out
Take a penny and reduce it by 28% for income taxes then double the $.0072 and reduce it again before doubling and so forth.The TOTAL income net of taxes is only $922.04.
There is a real lesson here. There is real power in doubling your money but only if you shelter it from taxation.
Tim
There is a great lesson here
April 18th, 2008 at 8:18 pm
edward fernandez said 2 raised to the 29th power was 1,073,741,823. Strange. I use a scientific calculator available on the internet (http://www.calculator.com/calcs/calc_sci.html) and I get 536870912. If I raise 2 to the 30th power, I get
1073741824.
April 23rd, 2008 at 8:04 am
edward fernandez made a basic mistake, it is the correct number but he forgot it was pennies (.01) and not dollars (1.00), so you divide by 100. The correct total for the 30 days is $10737418.23.
May 23rd, 2008 at 10:47 am
June 17th, 2008 at 1:17 pm
The scenario = “if you were given a choice to receive one million dollars in one month or a penny doubled every day for 30 days, which one would you choose?” The way this scenario is worded means that you will only receive 2 pennies every day for 30 days. ONE penny doubled (0.1×0.2) will ALWAYS equal .02! Reword the scenario and the title of this thread because it doesn’t make sense to choose a penny doubled every day over 1 million dollars.
June 25th, 2008 at 4:57 pm
June 28th, 2008 at 7:02 pm
you guys are so arguementative. “he is right, you are wrong!”. just get over it, their just numbers.
July 4th, 2008 at 7:16 pm
Okay…I just saw this on the happening. And I wasn’t sure about it, because the guy said that you would have over 10 000000$. So day 1 is 0.01$ and day 2 is 0.02$ and day 3 is 0.04$ and so on, but after day 30, do you add every day together? or just end with $5,368,709.12?
Anyone have a straight answer to this one
July 7th, 2008 at 4:52 am
Zoggy, You would have to add all the days together, per on day one you have .01 and day two you get .02 handed to you, So really on day two you would have a total of .03. So if you add everyday together, per your doubeling the previous days amount.
July 10th, 2008 at 9:31 am
Bottom line, doubling with a penny ads up quick IF you can stomach dropping 500k to TRY to double it with stocks. Start a mock portfolio with think or swim and put it to the test.
July 23rd, 2008 at 7:09 am
WOW, most of you are way too technical. It’s an analogy people. An example on how compounded efforts (and interest) work. For success to occur you need to give the most on the front end for a large of amount of time, but even though you may not see immediate results they are compounding and the pay off will occur if you have the tenacity and intestinal fortitude to stick with it. whatever “IT” may be.
By adding in the choice of the million in one month, it shows the danger of always going for the quick and easy. It may work out OK but you may be missing out on a much bigger and better deal.
August 10th, 2008 at 4:59 am
CARA, To get any particular day’s amount use this formula: 2 raised to the (n-1) power . To help you understand, on day 1 (n=1), the total for that day is 2 raised to the (1-1) power = 2 raised to the (0) power = 1. In fact, on day one you receive one cent. Likewise, on day 5 (n=5), the formula gives “2 raised to the 4th power (5-1)”, or sixteen cents.
To get the sum of all thirty days, use:(([SIGMA]2 raised to the (n-1) power)), n from 1 through 30
(this means you calculate the formula for the first day and then again for each succeeding day and you keep adding the totals every day), from 1 to 30. To get the sum up through any other number of days, just use that number of days for “n”. After you’ve tried this out a few times, here is a shortcut (actually this is the solution for the summation formula I gave above – the second formula with the Greek “sigma”).
The sum through “n” days is 2 raised to the (n)power less 1. So, on day 5 you have “2 raised to the 5th power less 1”, which is thirty-one cents, and that, indeed, is equal to the 1 cent, plus 2 cents, plus 4 cents, plus 8 cents, plus 16 cents (5th day), that you’ll get doing it the summation way (but now you understand).
Sorry, but this editor won’t allow me to paste the mathematical symbols/formulae (which would make this easier to read).
August 25th, 2008 at 2:31 pm
Thank you. Me and my dad were dicussing this and he didnt believe me. So than k you for doing this!!!!!!!!!!!!!
August 27th, 2008 at 1:29 pm
This was a GREAT blog! I’m at work right now contemplating actually doing this project…if only I can just get to day 28!
September 5th, 2008 at 6:00 pm
julian is correct, you have to now add all the numbers together, you get a penny on day one, two pennies on day two, 4 pennies on day three, at the end of 3 days you have 7 pennis, not four.
September 19th, 2008 at 4:09 pm
I knew this for years, the right answer is
$5,368,709.12 for 30 days.. 31 Days > 10,737,418.24
Thats What it is!
September 26th, 2008 at 2:03 am
If you get to keep your 1 cent the first day, two cents the second day, etc., you will have a total of $10,737,418.23 at the end of 30 days. THAT’S the correct answer. You don’t lose every single day’s investment and have it replaced by twice the amount. It adds up every day, like interest in the bank adds up.
October 7th, 2008 at 11:53 pm
[2^(n-1)]/100
October 14th, 2008 at 9:42 am
Here is the REAL DEAL answer to everyones questions!!
If you start with 1 penny(your principle) on day one and double it each day for thirty days (meaning that you are earning intrest then at the end of 30 days you will have 536,870,912 pennies which will be $5,368,709.12.
However, there is another scenario that says someone will pay you 1 penny on day 1 and double the amount they pay you on each additional day there after for 30 day. this means they pay you (1 penn on day 1) (2 pennies on day 2) (4 pennies on day 3) (8 pennies on day 4) and so on….. since they are paying you at the end of each day you keep the money from each day.
Therfore you will add up the total for days 1 through 30. this means they will have payed you
1,073,741,823 pennies or $10,737,418.23
October 14th, 2008 at 10:19 am
The actual formula is (2^n)-1 for your answer in pennies, divided by 100 for the answer in dollars.
EG: (2^3)-1=7
1+2+4=7.
Real answer is 10,737,418.23 for a thirty day month.
October 17th, 2008 at 7:22 am
This was hilarious! So many people needing to prove their answer was the right answer just got better and better as I read each entry. I was totally cracking up. Then, the tax issue. That just blew me away!
Thank you all for making a boring day bearable.
October 19th, 2008 at 6:09 am
I’m the dumb one here. But all my life I’ve loved gigantic numbers!!!!!!!!!!!!! Any way I was wondering what would be an easier way to figure the amount after 2 months 3 months etc.
October 31st, 2008 at 6:42 pm
November 1st, 2008 at 9:28 pm
Steigertiger you are the dumb one because the formula is listed ABOVE!!!!! Just put in the numbers and pooof the answer appears…Now if you cannot figure this out call hooked on phonics for numbers.
November 6th, 2008 at 6:00 pm
The calculation on day 24 is wrong, I believe it would be 83,886.08.
November 7th, 2008 at 1:41 pm
a 31 day month would be $24,159,320.76
that is the actual sum of all the days. =]
November 7th, 2008 at 3:54 pm
2 to the power of 30=1073741824 or 1073741824 pennies. 100 pennies make a dollar. 1073741824 divided by 100=$10,737,418.24. I don’t think I’m wrong but if I am o well.
November 8th, 2008 at 9:57 pm
No No Josh A, if that is your name,and we all know its propable not. A 31 day month would be $21,474,836.47 however I’m sure you have realized your mistake. By the way Gubble Bum you my friend are correct;-)
November 11th, 2008 at 1:07 pm
i think everyone is to analytical on the wording of the secerio its meant for fun. however for the people that are confused about whether you have 5 mill or 10 mill what is happening is that the amount of money you are given is doubled meaning that if you have 4 cents you are not given 8 cents the next day you are given 4 cents they are matching the money in a sense doubleing it everyday so on day 30 you have roughly 5 million dollars and on day 31 you will have 10 mill not 10 million on day 30 just cause you can add the numbers please take an accounting class to learn more
November 18th, 2008 at 8:43 am
It’s a great way to increase money, but interest doesn’t double your money. It’s only a fraction percentage of th eprincipal, which means you actually have to deposit the dobled amount. I don’t know about you, but I don’t have $167,000 to deposit on day 25 to double it!
Just my 2 cents worth (get it? 2 cents!)
November 19th, 2008 at 9:58 pm
shoot, i dont have the money i need to put in on day 12. what are you talking about?
but i sure would love to do this and get rich if i had it to do. lol.
shay.
November 25th, 2008 at 11:02 am
Ok… I teach high school math and a student posed this problem to me. I gave her an answer and she didn’t believe me, so we came across this in trying to verify. Here’s how I explained it to her…
Day 1 = 0.01 = 2^0(.01)
Day 2 = 2(0.01) = 2^1(.01)
Day 3 = 2(2(0.01)) = 2^2(.01)
Day 4 = 2(2(2(0.01))) = 2^3(.01)
and so on…
Day 30 = 2^29(.01) = 5368709.12
December 1st, 2008 at 1:50 pm
Okay I’m getting the same answer as most of you which is the total for 1 month is 10,737,418.23. I had to do this in my college math class. We were supposed to figure out that and then figure out how many DAYS it would take to become a googolaire….10 to the 100th power. Anyone know the answer to that???
December 3rd, 2008 at 5:29 pm
The answer is on a 30-day month, you would end up with $5,368,709.12. In a 31-day month, you would end up wih $10,737,418.24. You have 1 penny on day one, 2 pennies on day 2, 4 pennies on day three, and just keep doubling what you had the prior day for the next day. That is how you get this result.
December 4th, 2008 at 9:30 am
That is just saying how much you get paid each day. It’s not saying how much you made for the entire month.
Day 1: $.01
Day 2: $.02
Day 3: $.04
Day 4: $.08
Day 5: $.16
Day 6: $.32
Day 7: $.64
Day 8: $1.28
Day 9: $2.56
Day 10: $5.12
Day 11: $10.24
Day 12: $20.48
Day 13: $40.96
Day 14: $81.92
Day 15: $163.84
Day 16: $327.68
Day 17: $655.36
Day 18: $1,310.72
Day 19: $2,621.44
Day 20: $5,242.88
Day 21: $10,485.76
Day 22: $20,971.52
Day 23: $41,943.04
Day 24: $83,886.08
Day 25: $167,772.16
Day 26: $335,544.32
Day 27: $671,088.64
Day 28: $1,342,177.28
Day 29: $2,684,354.56
Day 30: $5,368,709.12
Add it all together and you get 10737418.23
December 4th, 2008 at 1:40 pm
thanks needed 2 figure it out 4 extra credit in class
December 6th, 2008 at 9:08 am
December 6th, 2008 at 9:09 am
suckers its all wrong he didnt carry over any thing i am always right
December 6th, 2008 at 9:09 am
December 6th, 2008 at 9:13 am
when do u check this stuff peeps rite
December 11th, 2008 at 11:02 am
I’d keep only one penny! (one from 1966). you can keep your million!
December 11th, 2008 at 11:46 pm
hahaha i asked this girl in my class if she would rather have a quarter a day for a month or a penny doubled everyday and she said “is that a trick question, a quater a day duhh!”
then i told her that with a penny doubled you get more than a million dollars and she wanted proof so thank you for all the proof i need! 
December 30th, 2008 at 12:04 pm
Every day, you only add enough pennies to double the amount. You don’t add twice the amount every day. Start with a penny.
But at the end of 30 days, you’d have $5,368,709.12. 
+1=2
+2=4
+4=8
+8=16
+16=32
+32=64
+64=128
+128=256
…and so on and so on. Every day, you match the previous day’s new sum. You don’t double it and then add the new amount. (Well, you could, if you have just that many pennies and wanted to really speed up the process).
If you were really ambitious and were to actually double the amount and THEN add the pennies, you’d end up with about $10,737,418.23.
Trust me….if I had the pennies to do this every day, I wouldn’t be working my 8-5 job.
January 5th, 2009 at 11:31 am
Guys! Gals! who cares if it gives 1 million, or 5 million, or 10 million, The point is, that it’s whatever million dollars richer than day 1!
January 8th, 2009 at 12:04 pm
impressive question. i’ve seen this on The Happening and my dilemma is: the final answer is with or without adding all days together?
and the amazing thing is that the amount earned in the 31st day is the same with the amount earned if 30 days are added together…
…i mean duh…they were doubled
i dont know its really addicting
January 23rd, 2009 at 9:29 am
If you are strictly doubling the money and the final answer is 5,368,709.12 the the equation is
(x)*2^t
x being the amount started with on day 1
t being the number of days
if the answer is all of the numbers added together at the end, then the equation is
((.01)*2^29)*2
February 19th, 2009 at 2:58 am
there are other pactical applications fo this equation
I do genealogy and have used this in figuring out the number of names that would be in a pedagree chart. In 45 generations there would be over 98 billion names.
February 27th, 2009 at 10:36 am
I been working on this for years in my life and it work for me.double a penny in 2 years not 31 days.and I know how it work!
March 2nd, 2009 at 3:33 pm
Don’t put on the powers it’ll give you the wrong answer if you actually try the doubling instead of finding a short cut you’ll get the right answer believe me I tried it. The final amount is $5,368,709.12. You don’t add the sums from all the days either
March 23rd, 2009 at 5:31 pm
I’D HAVE TO SAY I’D TAKE THE MILLION DOLLARS. Because there is no such thing as a “penny” in my country. It is a CENT. Since there are no “pennies”, it would make One Million Dollars a much more profitable venture!
March 27th, 2009 at 8:16 am
Sorry Steven but you are wrong. It does work using powers. It is called math and there is an equation for everything. You just have to know how to use it.
March 27th, 2009 at 1:50 pm
It is funny how everyone loses the point of teaching something like this. The point is sometimes we settle for less than the best by conceding in life. If we keep working our outcome will be better than settling on a less than perfect sure-thing. The last few days will in fact be our most productive if efforts are all-out until the end!
April 14th, 2009 at 9:34 am
another equation that could be used is the future value of a dollar equation. which is FV=PV(1+i)to the power of n
fv=0.01(1+1)to the 30th power
fv=.01 x 2 power 30
fv = 10,737,418.23
n= to the period which is 30 days ans i= interest factor which is 100% because it is getting doubled
so there u go another way
April 27th, 2009 at 5:27 pm
How do you figure this out using log on the calculator?
May 15th, 2009 at 6:01 pm
I know how to apply the scenario but it wouldn’t be in 30 days but even a year would be fine. Wouldn’t it?
Brian
May 18th, 2009 at 1:51 pm
sme people are saying that it wouls only be 0.02 cents every day because of the way its worded. while i fully understand how you got it isnt fully correct “a penny doubled every day for a month” is to have a penny double it, double it, double it, and so on as in the article.
it is a trick question they are supposed to trick you so you have been tricked, big deal who cares. it was meerly an article to get people to think in the long run.
May 24th, 2009 at 6:35 pm
What would be the formula to use if i was to design a program using a psuedocode? and the total has to be displayed in dollars.
May 28th, 2009 at 3:09 am
“A PENNY EARNED IS A PENNY SAVED.”
-A. LINCOLN- SO START SAVING NOT DOUBLING.
May 28th, 2009 at 8:10 am
…a penny saved is a penny earned…so start saving not doubling. here’s a very simple solution to that penny thing: 30 days=30 houses; on the 1st day you collected the 1st penny from the 1st house; 2nd day you collected 2 pennies from the 2nd house, and so on…at the end of 30 days, you have collected a total of 536,870,912 pennies which is = to $5,368,709.12. it means, there are no more pennies left among those 29 houses. thus, $10,737,418.24 in 30 days is not possible. 31 days, yes.
one time i deposited a gallon of pennies in the bank. do you know how much? just about $30-ha-ha-ha. when usps started accepting pennies in vending machines, i used plenty of them to buy stamps.
May 28th, 2009 at 8:17 am
or maybe you can use a bar graph. don’t worry about that penny thing. someday soon the govt. will phase out that coin.
June 2nd, 2009 at 8:36 am
I might only be 14 but i can tell you one thing dont matter what you get money you probly didnt have before so be thankful they put this site on for us!!
:):):):):):):):):):):):)
June 2nd, 2009 at 8:43 am
June 2nd, 2009 at 11:00 am
i JUSZ Wanted to leave a comment
June 21st, 2009 at 9:45 pm
OK now, I’ll settle this as this was looked at in many angles..First of all, I’m a retired math ‘guru’, if you will’ and it boggles my mind that some of the younger people on this subject were right and the so called math teacher was absolutely dead ‘WRONG’. Congrats to all you smart ones for looking at this with open minds and for the block heads out there here ARE the REAL FACTS: Sorry to…Stephen,DCecil21,certified ilokano american, Christene, and Shanna the math teacher…you are all wrong, you don’t need a 31st day to get the totel. You ABSOLUTELY DO need to add all the days because what you faled to realize is the fact that you KEEP ALL the pennys you recieve on EACH day. Look at the key words here and there’s a point in there. Gubble Bum, Mitchell-licous, Alisha, 2muchtime, and Josh are ALL CORRECT!!!!!! Pay GOOD attention to questions before you decide to give a dumb answer..(example) Every day you add the ‘doubled’ amount to ‘each’ total you got ‘each’ day so the total IS TRUELY>>> $10,737,418.23. THIS IS IT!!! NO IF’S AND’S OR BUT’S….
June 21st, 2009 at 9:57 pm
EXAMPLE # 2: You add day one total to day two total then you add both totals from day 1 and day 2 to day three then you add all three days to day 4 total and so on. If you still don’t get it, get help soon you poor souls,this isn’t that hard. ( the key word here is (DOUBLE) SO ‘YES’ the final number of 5,368,719.12 is ‘doubled’ because ALL the totals get added to give you $10,737,418.23 IS in only 30days NOT 31!!!!!!!
June 21st, 2009 at 10:08 pm
EXAMPLE #3…If this last example doesn’t prove the fact then the few of you who think you’re right REALLY need help…. On day one you get .01 on day ten you get 5.12 for ‘that day only’ on day 20 you get 5242.88 for ‘that day only’ on day 30 the amount of 5,368,709.12 is the amount you got for THAT DAY ONLY so THINK REAL HARD, what happened to the 2,684,354.56 you got the day before??? You STILL have what you got the day before and every day before that so this shows that you DO add EVERY SINGLE DAY TO EACHOTHER to give you $10,737,418.23 in 30 days. (THE END)
June 21st, 2009 at 10:25 pm
By the way, under a certain law wich was imposed a few years back that deals with anything we see on tv or movies or hear on radio certain facts MUST be mentioned CORRECTLY in non-science fiction movies. Tha reason I mention this is because in the movie “The Happenning” actor John Leguizamo brought up this ‘penny doubled’ thing and HE gave the correct answer. This is only imposed to anything considerd educational info in movies since so many people are influenced by what they see in movies and though this movie is not a true story, the basic idea is (’what if’) this movie teaches to think “what if”………………..
June 21st, 2009 at 10:57 pm
OK I had to come back on this cuz i read every comment and saw a lot of confusion on wording so I will once again settle this since I actually have the CORRECT wording in my hands as we speak:::: “If I gave you 1 penny today, 2 pennies tomorrow, 4 pennies the next day and keep doubling each days total every day after, how much will you have after 30 days?” The ONLY TRUE ANSWER IS $10,737,418.23 AS YOU WOULD “ADD” EACH AND EVERY DAY’S TOTAL TO EACHOTHER and that’s that.
June 29th, 2009 at 11:00 pm
Ok I’d like to comment on something that is causing
the comotion. It’s looking at the problem
from 2 scenarios. Some people are trying to multiply
by 2 and some are squaring when they should be
multiplying that days number times
itself for the next days amount.
Proof: Ok say John hits lottery and gives Lori $100
dollars ond Monday(Day 1). She’s so excited, but John
isn’t through yet. He tells her if she doesn’t spend and of $100
bucks, and she puts it in an envelope, the next day(DAY 2) he will
DOUBLE what is in envelope. looks inside, crisp $100 bill. Now it’s simple.
To double it, he must place ANOTHER $100 inside.
To her surprise, he continues on third day. Inside envelope
Lays Lauras $200. Think of double or nothing bet. Now he will place
$400 bucks inside.
Day 1 : $100 1 cent
Day 2 : $200 2 cents
Day 3 : $400 4 cents
Day 4 : $800 8 cents
Day 5 : $16,000 1,600 cents
Now this seems simple. BUT, depending on how you
take the question is the key: BOTH WAYS ARE RIGHT
Day 1 : $100
Day 2 : $200
Day 3 : $400
Day 4 : $1,600
Day 5 : $2,560,000
so if John doubles previous amount following Day 30, then
over 10 mill….
July 19th, 2009 at 7:12 am
Day 1 = $0.01 (Now in total you have $0.01)
Day 2 = $0.02 (Now in total you have $0.03)
Day 3 = $0.04 (Now in total you have $0.07)
Day 4 = $0.08 (Now in total you have $0.15)
Day 5 = $0.16 (Now in total you have $0.31)
Day 6 = $0.32 (Now in total you have $0.63)
Day 7 = $0.64 (Now in total you have $1.27)
Day 8 = $1.28 (Now in total you have $2.55)
Day 9 = $2.56 (Now in total you have $5.11)
Day 10 = $5.12 (Now in total you have $10.23)
Day 11 = $10.24 (Now in total you have $20.47)
Day 12 = $20.48 (Now in total you have $40.95)
Day 13 = $40.96 (Now in total you have $81.91)
Day 14 = $81.92 (Now in total you have $163.83)
Day 15 = $163.84 (Now in total you have $327.67)
Day 16 = $327.68 (Now in total you have $655.35)
Day 17 = $655.36 (Now in total you have $1310.71)
Day 18 = $1310.72 (Now in total you have $2621.43)
Day 19 = $2621.44 (Now in total you have $5242.87)
Day 20 = $5242.88 (Now in total you have $10,485.75)
Day 21 = $10485.76 (Now in total you have $20,971.51)
Day 22 = $20971.52 (Now in total you have $41,943.03)
Day 23 = $41943.04 (Now in total you have $83,886.07)
Day 24 = $83886.08 (Now in total you have $167,772.15)
Day 25 = $167772.16
(Now in total you have $335,544.32)
Day 26 = $335544.32
(Now in total you have $671,088.63)
Day 27 = $671088.64
(Now in total you have $1,342,177.27)
Day 28 = $1342177.28
(Now in total you have $2,684,354.55)
Day 29 = $2684354.56
(Now in total you have $5,368,709.11)
Day 30 = $5368709.12
(Now in total you have $10,737418.23)
If your answer is 100 times greater than $10,737,418.23 you have to remember you started in pennies. There are 100 pence in every dollar. So the answer is $10,737,418.23.
End of Question.
July 29th, 2009 at 12:41 pm
What If It’s A 31 Day Month
August 4th, 2009 at 9:31 pm
Thats it! I’m calling the FTC. Your all out of order, this whole thread is out of order!
I’m ending this right now…..
This has nothing to do with math. As others have eluded too. It is an issues of semantics…nothing more, nothing less. It is evident from the posts…that most of us can do the math…be it long hand or with a sci calculator, or if your a self proclaimed genius like myself…then you are fortunate enough to just run the numbers in your head and whala!
So really, it never should have been a discussion about math…but rather–a discussion about semantics.
Wait a minute! It should not have been a discussion about either of those things. What the hell was the point of the original post anyway?
See! Thats why I’m calling the FTC…there is trickery going on here, and I’m going to get to the bottom of it.
Incidentally, my interpretation of the post would have been the same as the authors. But I refuse to even mention a number…after having witnessed the blasphemous rantings of the masses.
So, in conclusion: Most of you neophytes meandered down the wrong path.
I can just feel the love already.
August 20th, 2009 at 9:30 am
September 18th, 2009 at 9:06 am
Now let me tell you why this is wrong. Im going by your answers. You said by the end of the 30 days the pennies total 10,737,418.23 right? now what you are forgetting is this is the total amount in pennies. so 100 pennies equal $1.00 right? so you divide 10,737,418.23 by 100 and you only get $107,374.18 in dollars. This number is far from millions. So which make this NOT TRUE.
September 24th, 2009 at 2:56 pm
Moe is absolutely right. I was wondering when the smartest person in the world was going to appear,but there is one exception it’s not that total on the 30th day that’s the total for day 31( 10,737,418.23)
September 24th, 2009 at 4:55 pm
This was on the movie The happening, I didn’t understand the joke the guy told before the car crashed so I had to search it up on the internet, thankyou.
October 15th, 2009 at 6:20 am
Just tossing it out there, you don’t add them all together. It states that the amount is double each day. This means on day 1 you have one penny, and on day two :::you only receive one penny, this would make 1+1=2 (doubled) therefore you don’t have three pennies after day two, you only have two. ect…
October 15th, 2009 at 6:06 pm
thx dude i needed this for my math hw
October 17th, 2009 at 12:21 am
Now someone tell me this…If you start with a penny and double it everyday for 1 year, how much will you have then?
October 26th, 2009 at 4:22 pm
this is the (retardedest
)thing i have ever read
November 4th, 2009 at 8:58 pm
a penny doubled everyday for 30 days is only sixty cents on day 30 !!!!!!!!!!
day 1= .02
day 2= .02 and so-on until day 30 and he didn’t compound the totals of each day.It’s only two cents per day people.
November 26th, 2009 at 5:33 pm
Gotta love people who don’t understand exponential growth.
Here’s a quick, effortless way to figure this out.
1. Open Microsoft calculator.
2. Hit 1 * 2 =
3. Keep hitting = as many times as you’d like.
4. Experience exponential growth.
Also, doing this with pennies and a calendar is dumb. This question was originally asked with grains of wheat/rice placed on a chess board (over the total of 64 squares you’d have 18,446,744,073,709,551,615 grains of wheat/rice).
December 29th, 2009 at 5:37 pm
Wow, ummmn… this whole thread was unexpectedly funny.
Many are right in one way and wrong in another depending on interpretation. A simple concept of compound interest is approaching the complexity of a theological debate with multiple beliefs being related with each more adamant than the last about it’s own validity. Pretty soon this is going to have to be moved to a comparative religions thread in order for the discussion to fit the topic.
Several people have proving adequate math skills, it seems more the interpretation of the original premise that seems to be in question. As far as that goes … outside of a classroom it no longer matters what is said or meant once a thing is uttered. It only matters what a person hears or understands it to mean.
So to all of you with the adequate math skills… you are all right within the constructs of your own paradigm.
that’s my 2 bits as I couldn’t help but comment myself for some reason.
January 15th, 2010 at 6:51 am
Wording is wrong. A penny doubled for 30 days. well isn’t that just 2 pennies everyday for 30 days? or 60 cents?
February 8th, 2010 at 1:25 am
This was on an episode of walker texas ranger. and walker played by chuck norris gave the answer $5,368,709.12 so that has to be right because what Chuck Norris says goes! end of story.