JAMB Mathematics 2023 Paper

Concept:The total work done is constant, so compare total man-hours for both groups of workers.Explanation:Total work needed = $12$ men $\times 8$ hours/day $\times 4$ days = $384$ man-hours.Let the required number of days be $d$.Work done by $4$ men working $16$ hours a day for $d$ days is $4 \times 16 \times d$.Equate the two amounts of work:$$4 \times 16 \times d = 12 \times 8 \times 4$$$$64d = 384$$$$d = \frac{384}{64} = 6$$Therefore, $4$ men working $16$ hours a day will complete the same piece of work in $6$ days.Answer:6 days (Option A)