Question

Find the sum of an 8-term geometric sequence when the first term is 7 and the last term is 114,688 and select the correct answer below.

152,915
16,384
16,377
152,908

Answer 1

@superhelp101 @welshfella @paki @butterflydreamer @ganeshie8

Answer 2

you are given a
you are given Sn the sum of the terms
do you know the formula for the sum of the terms?

Answer 3

Sn = a1 - a1rn/ 1 - r

Answer 4

what you are not given is r, the common ratio.

Answer 5

Are you sure you weren't given a common ratio, r, in the question?

Answer 6

\[a,ar,ar^2,ar^3,...,ar^7 \\ \\ \text{ you are given } ar^7=114688 \text{ and } a=7 \\ \text{ so you can find } r \\ \text{ just solve } 7r^7=114688 \text{ for } r \]