Multiple choice

40 men can do a piece of work in a given time. If only 30 men be engaged, 6 more days are needed to complete the work. In how many days can 60 men do the work?

  1. 9

  2. 10

  3. 12

  4. 15
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let d be the number of days for 40 men. Work = 40d man-days. With 30 men: 30(d + 6) = 40d, so 30d + 180 = 40d, giving d = 18 days. Total work = 40 × 18 = 720 man-days. With 60 men: days = 720/60 = 12 days. Alternatively, 60 men is 1.5 times 40 men, so time is 18/1.5 = 12 days.

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