Question

18 men can complete a piece of work in 5 days. In how many days can 21 men complete the same piece of work?

Answer 1

18 men can complete the work in 5 days.

So, 1 man can complete the work in 5×18= 90 days

∴ 21 men can complete the work in $\frac{90}{21}$≈ 4.3 days or about 102 hours.