Multiple choice

20 men can complete a work in 50 days, working for 5 hours a day. After 15 days from the start of work, 10 men quit. How many hours per day do the remaining men have to work so as to complete the work on time?

  1. 6 hours

  2. 8 hours

  3. 10 hours

  4. 12 hours

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Initial work is 20 men * 50 days * 5 hours = 5000 man-hours. After 15 days, 20 * 15 * 5 = 1500 man-hours are done, leaving 3500 man-hours. With 10 men remaining, they must work 3500 / (10 * 35 days) = 10 hours per day.

AI explanation

Using the man-hours formula M1D1H1 = M2D2H2 + M3D3H3, the total required man-hours are 20 x 50 x 5 = 5000. The first phase uses 20 x 15 x 5 = 1500 man-hours, leaving 3500 man-hours. For the remaining 35 days with 10 men, the equation becomes 3500 = 10 x 35 x H2, yielding H2 = 10 hours per day.

Keep practicing — related questions