Answer : The first three terms of a G.P. are:a,ar,ar2 The first six terms of a G.P. are:a,ar,ar2,ar3,ar4,ar5

It is given that the ratio of the sum of first three terms is to that of first six terms of a GP is 125 : 152.

⇒ a + ar + ar2 = 125x & a + ar + ar2 + ar3 + ar4 + ar5 = 152x

⇒ a + ar + ar2 + r3( a + ar + ar2) = 152x

⇒ 125x + r3(125x) = 152x

⇒ r3(125x) = 152x – 125x = 27x

⇒ r = 3/5

Ans: common ratio =

3/5