View Full Version : More mathematics fun .
ROLCAM
Mar 28, 2009, 03:46 AM
If you accepted a deal that has you earn a penny on the first day, and earn doublings for the next 30 days, how much would you have in your bank account by the 30th day?
adam_89
Mar 28, 2009, 04:25 AM
That is a fun one. I was always asked would you rather have a million dollars or a penny doubled everyday for a month. Instinctively you would say the million dollars, but actually the Penny doubled everyday is much larger I will get you the number in a sec.
adam_89
Mar 28, 2009, 04:30 AM
The answer is $5,368,709.12 I will show the order in just a sec
adam_89
Mar 28, 2009, 04:37 AM
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
adam_89
Mar 28, 2009, 06:23 AM
What do you mean Excel is very helpful?
galactus
Mar 28, 2009, 06:43 AM
Just that, generate them with Excel. Use 2^N and drag it down
adam_89
Mar 28, 2009, 08:48 AM
Just that, generate them with Excel. Use 2^N and drag it down
Ok, I believe you are referring to Microsoft Excel? The formulas that you use to quickly add things sometimes? I didn't think about that. I used a piece of paper and a calculator for most of it. LOL
galactus
Mar 28, 2009, 05:16 PM
Take note that 2^{29}=536870912
We use to the 29th power because of 2^0=1 on the first day.
adam_89
Mar 30, 2009, 07:30 AM
Ok, I am not disagreeing with you or anything, I was just saying that I didn't use that. Sorry for any misunderstandings.
galactus
Mar 30, 2009, 07:42 AM
That's fine. You're method was good. Just 'brute force', as they say.:)
adam_89
Mar 30, 2009, 08:36 AM
Ok, thank you.