Question

4 men and 12 boys can do a piece of work in 5 … days by working 8 hours per day. In how many days 2 men & 4 boys can do the same piece of work working 12 hours a day.

Answer 1

Given 4 m = 12 B 

1 m = 3 B

2 men & 4 boys = 6 boys + 4 boys = 10 boys

Boys & days are in inverse proposition days & hours are in inverse proportion. 

∴ 10 : 12 :: 5 : x 12 : 8

x = \(\frac{12\times8\times5}{10\times12}\) = 4 days.