Question 8

The sum of some terms of G.P. is 315 whose first term and the common ratio are 5 and 2, respectively. Find the last term and the number of terms.

Answer

Let the sum of *n* terms of the G.P. be 315.

It is known that,

It is given that the first term *a* is 5 and common ratio *r *is 2.

∴Last term of the G.P = 6th term = *ar*^{6} ^{– 1} = (5)(2)^{5} = (5)(32) = 160

Thus, the last term of the G.P. is 160.

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