36 workmen are employed to finish a certain work in 48 days. But it is found that in 24 days only 2/5 work is done. How many more men must be employed to finish the work in this?

Let N men are employed.
Given, M₁ = 36, M₂ = 36 + N, D₁ = 24,
D₂ = 24, W₁ = 2/5, W₂ = 1 - 2/5 = 3/5
According to the formula M₁D₁W₂ = M₂D₂W₁
⇒ 36 x 24 x (3/5) = (36 + N) x 24 x (2/5)
⇒ 36 x 3 = 2(36 + N) ⇒ 108 = 72 + 2N
∴ N = 36/2 = 18 men