4 men can complete a piece of work in 5 days, 5 women can complete it in 8 days, and 10 children can complete it in 6 days. In how many days can 2 men, 2 women and 3 children together complete the same work?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 5
Fewer people take proportionally longer, so first find the time for one person of each kind.
1 man takes \(4\times5=20\) days, 1 woman \(5\times8=40\) days, 1 child \(10\times6=60\) days
One-day work of 2 men, 2 women and 3 children \(\displaystyle =\frac{2}{20}+\frac{2}{40}+\frac{3}{60}=\frac{6+3+3}{60}=\frac{1}{5}\)
They complete the work in 5 days.