16 children and 24 men complete a certain work for 18 days. If each child takes twice the time taken by a man to finish the work in how many days will 24 men finish the same work?

According to the question,
2 children = 1 man
∴ (16 children + 24 men) = (8 + 24) men = 32 men
Given M₁ = 32, M₂ = 24, D₁ = 18, D₂ = ?
and W₁ = W₂ = 1
According to the formula, M₁D₁W₂ = M₂D₂W₁
⇒ 32 x 18 x 1 = 24 x D₂ x 1
∴ D₂ = (32 x 18)/24 = 8 x 3 = 24 days