Latest TCS Aptitude Question SOLUTION: s= 1/7 + 3/7^2 +7/7^3 + 13/7^4 + ........ s = ? answer 25/108

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(#M40038895) TCS Numerical Ability question Keep an EYE

s= 1/7 + 3/7^2 +7/7^3 + 13/7^4 + ........
s = ?
answer 25/108

Asked In TCS hima (9 years ago)

Unsolved Read Solution (4)

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Read Solution (4) :

RAKESH  (9 years ago)

s= 1/7 + 3/7^2 +7/7^3 + 13/7^4 + ........
s/7 = 1/7^2 + 3/7^3 + 7/7^4 + .....
----------------------------------------------------
=> s- s/7 = 1/7 + 2/7^2 + 4/7^3 + 6/7^4 ....
-----------------------------------------------------
=> 6s/7 = 1/7 + 2/7^2 + 4/7^3 + 6/7^4 + ...
=> 6s/7^2 = 1/7^2 + 2/7^3 + 4/7^4 + ....
-----------------------------------------------------
=> 6s/7- 6s/49 = 1/7 + 1/7^2 + 2/7^3 + 2/7^4 + ....
=> 36s/49 = 1/7 + 1/49 + 2(1/7^3 + 1/7^4 + 1/7^5 +...)
=> 36s/49 = 8/49 + 2* 1/7^3 / (1- 1/7) = 25/49*3

=> s = 25/108

Is this solution Helpfull? Yes (16) | No (3)  

hima  (9 years ago)

@rakesh 25/49*3 is not 25/108 its 25/147

Is this solution Helpfull? Yes (3) | No (5)  

vignesh  (9 years ago)

@hima whr did u gets these questions pls?????????????????

Is this solution Helpfull? Yes (1) | No   

Sourav Nayak  (2 years ago)

By solving the answer is 25/147
Can you tell me what's the exact answer is?
@Hima

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