Aptitude:: Time and Work

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A and B can do a job together in 7 days. A is times as efficient as B. The same job can be done by A alone in :

A.

B. 11 days
C.

D.


Answer: Option B

Explanation:

 

(A's 1 day's work) : (B's 1 day's work) = 7 : 1   =   7 : 4.
4

 

Let A's and B's 1 day's work be 7x and 4x respectively.

Then, 7x + 4x = 1     =>     11x = 1     =>     x = 1 .
7 7 77

 

Therefore A's 1 day's work = ( 1 x 7 ) = 1 .
77 11

 


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