Multiple choice

A man and a woman, working together can do a work in 66 days. The ratio of their working efficiencies is (3 \colon 2). In how many days 6 men and 2 women together can do the same work?

  1. 15

  2. 14

  3. 12

  4. 18

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

Let man's efficiency be 3 units/day, woman's be 2 units/day. Together they do 5 units/day. In 66 days, total work = 66 × 5 = 330 units. Now 6 men and 2 women have combined efficiency = 6×3 + 2×2 = 18 + 4 = 22 units/day. Time = 330/22 = 15 days. The key is converting efficiency ratios to actual work units per day.