Question

Find the sum of the first 9 terms in the following

geometric series.
Do not round your answer.
64 + 32 + 16 + ...

Answer 1

127.75

Explanation:

Answer 2

127 3/4

Explanation:

you are just dividing the previous term by 2.

4th: 16 / 2 = 8

5th: 8 / 2 = 4

6th: 4 / 2 = 2

7th: 2 / 2 = 1

8th: 1 / 2 = 1/2

9th: 1/2 / 2 = 1/4

Add in groups of three to make it easier.

64 + 32 + 16 = 112

8 + 4 + 2 = 14

1 + 1/2 + 1/4 = 3/2 + 1/4 = 1 3/4

112 + 14 + 7/4 = 127 3/4