Tuesday, November 4, 2008

If you had a penny...

Watching The Happening last night, John Leguizamo asks a girl a math riddle...

If I gave you a penny for Day 1, 2 pennies for Day 2, and 4 pennies for day 3, and I continued doubling the amounts over the next 31 days, what would the total be on the 31st day?
(answer below)




Here's the math:
Day 1 $0.01
Day 2 $0.02
Day 3 $0.04
Day 4 $0.08
Day 5 $0.16
Day 6 $0.32
Day 7 $0.64
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
Day 31 $10,737,418.24


Guess that's why stealing a "fraction of a cent" in Office Space didn't work too well.

2 comments:

Amanda said...

Actually...I'm wondering if it's not an even larger number. If you read it as "today you get double what you got yesterday," then there's still some addition to do, right? Because isn't he asking how much money total you'd have by the end of the month? So...on Day Two, you'd actually have three pennies because you got one on Day One and two on Day Two. Which means you'd have a ridiculously large amount of money by Day 31. I guess it ultimately depends on whether or not you get to keep yesterday's money when you get the double amount today.

Amanda said...

So...then it's like...if it were doubled every day for 31 days, what would the amount be on day 31? Rather than what is the total amount in your pocket on day 31? (I mean, unless you don't get to keep the previous day's money...I dunno. I suck at these things.)