48 persons can complete a piece of work in 35 hours. In how many hours will 20 persons do it?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 84 hours
The amount of work stays the same, so persons × hours is fixed: fewer persons need proportionally more hours.
Total work in person-hours (one person working for one hour is the unit): \(48\times35=1680\)
The same 1680 person-hours shared among 20 persons: \(1680\div20=84\) hours