#3**+10 **

If it starts at 1 and doubles everyday:

.01 on day 1

.02 on day 2

.04 on day 3

.08 on day 4

16

32

64

`

`

`

536,870,912 pennies on day 30

ElectricPavlov Sep 18, 2016

#2**+5 **

If you mean the penny's value doubles every day, then do this: \(0.01*{2}^{30}\)

Since \(0.01*{2}^{30}\) = **10 737 418.24**, the penny would be worth that much in 30 days.

However, you have not specified what the exponent is. So, just replace the base of \({2}^{30}\) with whatever your exponent is. If the penny's value x10 every day, then change it to: \({10}^{30}\)

.jdtech Sep 18, 2016

#3**+10 **

Best Answer

If it starts at 1 and doubles everyday:

.01 on day 1

.02 on day 2

.04 on day 3

.08 on day 4

16

32

64

`

`

`

536,870,912 pennies on day 30

ElectricPavlov
Sep 18, 2016

#4**+5 **

**EP** what you write here really can’t be true.

*If it starts at 1 and doubles everyday:*

*.01 on day 1*

*. . . *

If the amount (a penny on day one) doubles everyday how can you have the same amount? It did not double on day one. (This reminds me of a few crooked bankers).

Start with a penny on day “zero.” The decimal counting system starts with zero, not one (1). If you look at it this way, it’s more clear.

_{ (Expanding the window will align the text and numbers)}

Comparsion to

Day 2^(day number) Total grains (of rice) on a chess board,

where the previous square’s amounts are added.

Note the first square is square zero.

0 1 1

1 2 3

2 4 7

3 8 15

4 16 31

. . . . . . . . .

28 268435456 536870911

29 536870912 1073741823

30 1073741824 2147483647

--------------------------

Remember: “A penny learned is a penny earned”

GingerAle Sep 18, 2016

#5**0 **

It all depends on how you interpret the question.....I guess both could be viewed as correct.

My view:

If you put the penny in a bank (that would be day 1).....it would not be doubled until the next day (day2). The penny does not double on the first day....it would be double after 24 hours, otherwise you are STARTING with two pennies.

But I can see it your way too...except if you have a day ZERO and then compute for 30 more days you are using 31 days, not 30. YMMV !!!

ElectricPavlov
Sep 18, 2016

#6**0 **

I guess I would see it better as doubling it 30 TIMES as opposed to doubling it 30 DAYS. !!!

ElectricPavlov
Sep 18, 2016

#7**0 **

But according to all of our former banking questions the interest rate would be 100% compounded daily for 30 days with an P of 1 cent, which would yield:

Fv = Pv (1+1)^30 = 1 (2)^30 = 107341824 at the end of the 30th day....as y'all calculated.....you are right!

ElectricPavlov
Sep 18, 2016