How many men need to be employed to complete a job in 5 days, if 15 men can complete 1/3 of the job in 7 days?

 a) 20
 b) 25
 c) 45
 d) 63

SSC CHSL-2014

63. Solution 15 men can complete the work in 21 days. So work done by one = 1/(21 x 15) Work completed in 5 days by a man = 5/(21 x 15) = 1/63 So Number of men needed to complete the work in 5 days is 63.