Question

7. The fifth term of a G.P. is 1875. If the first term is 3, find the common ratio.

Answer 1

Hi ,

Let first term and common ratio of G.P be

a and r ,

nth term = a × r^n - 1

Here ,

n = 5 ,

a = 3 ,

a5 = 1875 ( given )

ar^4 = 1875

3 × r^4= 1875

r^4= 1875/3

r^4 = 625

r^4 = 5^4

r = 4

[ since , if a^m = a^n then m = n ]

Therefore ,

Required common ratio = r = 4

I hope this helps you.

: )