Multiple choice general knowledge math & puzzles

15 men take 21 days of 8 hrs. each to do a piece of work. How many days of 6 hrs. each would it take for 21 women if 3 women do as much work as 2 men?

  1. 15

  2. 20

  3. 25

  4. 30

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

15 men × 21 days × 8 hours = 2520 man-hours total work. Since 3 women = 2 men, 1 woman = 2/3 man. 21 women = 21 × (2/3) = 14 men. Days needed = 2520 ÷ (14 × 6) = 2520 ÷ 84 = 30 days. Therefore 21 women working 6 hours daily would need 30 days to complete the same work.