If the sum of n terms of a G.P series is 225, the common ratio is 2 and the last term (nth term) is 128.

Question

asked Dec 24, 2020 146k views

2 Answers

Mepmerp · Answer 1 · 2020-12-26T00:41:24+0000

Answer:

n = 8.

Explanation:

I am assuming that the sum is 255.

The last term is 128 and the common ratio is 2 so we can work backwards until we reach a sum of 255.

Term n = 128 so the previous term must be 128/2 = 64.

So following this pattern we have:

128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 = 255.

So we see that n = 8.