Math Homework?

1st pizza: $15.99

2nd pizza -half of first: $15.99/2

3rd pizza -half of second: $15.99/4

4th pizza - half of third: $15.99/8

notice that the numerator is always $15.99 and the denominator for each is a power of 2.

..................

so the Nth pizza will cost: $15.99/[2 to the (N-1) power]

***why is is 2^ (N-1) power? Just look at the first 4 terms above..for the 2nd pizza the denominator is 2^1; for the 3rd pizza the deniminator is 2^2; for the 4th pizza the denominator is 2^3...always one behind!

31.75 = 15.99 + 15.99/2...+15.99/(2^(n-1))

31.75 = 15.99 (1 + 1/2 +....+1/(2^(n-1)) )

n=7

OR, very simple...

Total =31.75 so just keep adding prices until u get to the 31.75

1st pizza - approx $16

2nd pizza -approx $8

3rd pizza -approx $4

4th pizza-approx $2

5th pizza-approx $1

6th pizza-approx $.50

7th pizza-approx $.25

first, just round the 15.99 to 16. So the first pizza costs $16, ($16) so the second costs $8, ($24) so the third costs $4, ($28) so the fourth costs $2, ($30) so the fifth costs $1, ($31), so the sixth costs $.5, ($31.50), so the seventh costs $.25 ($31.75). So it's around 7 it think.

Seven pizzas (cost $31.74)