Multiple choice

18 men can complete a work in 25 days. After 4 days 3 more men joined the work. In how many days will the remaining work be completed?

  1. 18 days

  2. 19 days

  3. 20 days

  4. 21 days

  5. None of these

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

18 men × 25 days = 450 man-days total work. After 4 days, completed work = 18 × 4 = 72 man-days. Remaining work = 450 - 72 = 378 man-days. Now 21 men work (18+3 joined). Days needed = 378 ÷ 21 = 18 days. This uses the man-days concept where Men × Days = constant work.