Multiple choice

15 men can finish a work in 20 days, however it takes 24 women to finish it in 20 days. If 10 men and 8 women undertake to complete the work, then they will take.

  1. 10 day

  2. 20 day

  3. 15 day

  4. 30 day
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

15 men in 20 days means 15M × 20 = 1 work, so 1 man-day = 1/300 work. Similarly, 24W × 20 = 1 work, so 1 woman-day = 1/480 work. Combined rate of 10 men and 8 women = 10/300 + 8/480 = 1/30 + 1/60 = 3/60 = 1/20. Time = 1/(1/20) = 20 days.

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