Chain Rule Q38

38. 12 men working 8 hours per day complete a piece of work in 10 days. To complete the same work in 8 days, working 15 hours a day, the number of men required, is:

[A]4

[C] 6

[B]5

[D] 8

Answer : D

Explanation :

Let the required number of men be x.

Less days, More men (Indirect Proportion)

More working hrs per day, Less men (Indirect Proportion)

Days 8 : 10 Working Hrs 15 : 8  :: 12 : x

8 x 15 x x = 10 x 8 x 12

x = 10 x 8 x 12 8 x 15

x = 8