Q.

In a geometric progression the ratio of the sum of the first 5 terms to the sum of their reciprocals is 49 and sum of the first and the third term is 35.The fifth term of the G.P. is

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a

7/4

b

7

c

7/2

d

7/8

answer is C.

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Detailed Solution

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Let five terms in G.P. be ar2, ar, a, ar, ar2

Then ar2+r1+1+r+r2(1/a)r2+r+1+r1+r2=49

 a2=49a=±7.

Also, ar2+a=35

Therefore a =  7 is not possible

Thus, a=7 and a/r2=28.

Now, fifth term =ar2=aa28=74

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