The sum of an infinite G.P. is 57 and the sum of their cubes is 9747, then the common ratio of the G.P. is

Options

A. 1//2`
B. `2//3`
C. `1//6`
D. none of these

Explanation

Let a be the first term and r be the common ratio of the given GP.

Then, `a+ar+ar^2+....∞=57`


`a/(1−r​)=57
`

cubing`(a^3)/(1−r)^3​=(57)^3` .......(i)



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