Question

A man undertakes to do a certain work in 150 days. he employs 200 men. he finds that only a quarter of the work is done in 50 days. the number of additional men that should be appointed so that the whole work will be finished in time is

Answer 1

200 men in 50 days only completed 1/4 work.
Work remaining = 1 - 1/4 = 3/4 work

M1*D1/W1 = M2*D2/W2   ... [M1,M2:Men; D1,D2:Days; W1,W2:Work]
Let the number of men to be added be 'x'

200*50/(1/4) = (200+x)*100/(3/4)
200*50*4 = (200+x)*100*4/3
300 = 200 + x
x= 100
So, number of additional men that should be appointed to complete the work in time is 100.
Hope this helps.