Time and Work - Arithmetic Aptitude Questions and Answers

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A works twice as fast as B. If B can complete a work in 12 days independently, the number of days in which A and B can together finish the work in

4 days

6 days

8 days

18 days

Answer : Option A

Explanation :

Ratio of rates of working of A and B = 2 : 1.

So, ratio of times taken = 1 : 2.

B's 1 day's work = $\frac { 1 } { 12 }$

A's 1 day's work = $\frac { 1 } { 6 }$ ; (2 times of B's work)

(A + B)'s 1 day's work =[ $\frac { 1 } { 6 }$ + $\frac { 1 } { 2 }$ ]= $\frac { 3 } { 12 }$ = $\frac { 1} { 4 }$