(Q11).Find the common ratio of the GP 25, -5, 1,
-1
5

We know that if the first, second, third .... terms of a GP are a1 , a2 , a3 .... respectively

the common ratio r =
a2
a1
 =
a3
a2
 = ......

Here a1 = , a2 = -, a3 = .

So common ratio r =
-
 =
-
 =
-