Time and Work - Arithmetic Aptitude Questions and Answers

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A is 30% more efficient than B. How much time will they, working together, take to complete a job which A alone could have done in 23 days?

11 days

13 days

20 $\frac { 3 } { 17 }$ days

None of these

Answer : Option B

Explanation :

Ratio of times taken by A and B = 100 : 130 = 10 : 13.

Suppose B takes x days to do the work.

Then, 10 : 13 :: 23 :

x x = $[\frac { 23*13 } { 10}]$ x = $\frac { 299 } {10 }$

A's 1 day's work = $\frac { 1 } { 23 }$

B's 1 day's work = $\frac { 10 } { 299 }$

(A + B)'s 1 day's work =[ $\frac { 1 } { 23 }$ + $\frac { 10 } { 299 }$ ]= $\frac {23 } { 299 }$ = $\frac { 1 } { 13 }$