Question

If 2nd term and 4th term of G.P are 1 and 1/4 respectively, which term is 1/128?

Answer 1

Answer:

let 1st term be a and common ration=r

ar=1(given)

ar^3=1/4(given)

dividing both eqn we get:

r=1/2

using value of r , a=2

now,

1/128=2×(1/2)^n

256=2^n

n=8