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

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

anonymous · Answer

@superhelp101 @welshfella @paki @butterflydreamer @ganeshie8

anonymous · Answer

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

anonymous · Answer

Sn = a1 - a1rn/ 1 - r

anonymous · Answer

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

anonymous · Answer

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

freckles · Answer

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