Multiple choice

20 men could do a piece of work in 30 days working 4 hours a day, 30 men worked for 20 days for 3 hours a day. Then all were laid off, except one. How many more days would it take the last man to complete the remaining work, working 10 hours a day?

  1. 20 days

  2. 30 days

  3. 40 days

  4. 60 days

  5. 80 days
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Total work = 20 * 30 * 4 = 2400 man-hours. Work done = 30 * 20 * 3 = 1800 man-hours. Remaining work = 600 man-hours. One man working 10 hours a day takes 600 / 10 = 60 days.

AI explanation

The total work is calculated as 20 men times 30 days times 4 hours, resulting in 2400 man-hours. The work completed by the 30 men is 30 times 20 times 3 hours, totaling 1800 man-hours, leaving 600 man-hours of work unfinished. Since the last man works 10 hours a day, he requires 600 divided by 10 days, which equals 60 days, to complete the remaining work.

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