The ratio of the sum of the first three terms is to that of the first 6 terms of a G.P. is 125 : 152. Find the common ratio.
Sum of GP for n terms = 
Sum of GP of 3 terms = 125
⇒ 
⇒ 
…(1)
Sum of GP of 6 terms = 152
⇒ 
⇒ 
…(2)
Dividing 1 by 2 we get
⇒ 
⇒ 
⇒ 
⇒ 125r3 + 125 = 152
⇒ 
⇒ 
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