Question

Find the sum of G.P. : 3, 6, 12, .........., 1536.

Answer 1

Given G.P. : 3, 6, 12, .........., 1536

Here,

First term, a = 3

Common ratio, r =`6/3` = 2  ...(∵ r > 1)

Last term, l = 1536

∴ Required sum = `(lr - a)/(r - 1)`

= `(1536 xx 2 - 3)/(2 - 1)`

= 3072 – 3

= 3069