A person employed a group of 20 men for a construction job. These 20 men…
2024
A person employed a group of 20 men for a construction job. These 20 men working 8 hours a day can complete the job in 28 days. The work started on time but after 18 days, it was observed that two-thirds of the work was still pending. To avoid penalty and complete the work on time, the employer had to employ more men and also increase the working hours to 9 hours a day. Find the additional number of men employed if the efficiency of all men is the same.
- A.
40
- B.
44
- C.
64
- D.
80
Attempted by 8 students.
Show answer & explanation
Correct answer: B
Answer: 44
Explanation:
Work done in the first 18 days by the original 20 men: 20 × 8 × 18 = 2880 man-hours. Call this one unit of work.
Two-thirds of the work is pending, so remaining work = 2 units = 2 × 2880 = 5760 man-hours.
Each man working 9 hours/day for the last 10 days provides 9 × 10 = 90 man-hours.
Number of men needed in total to supply 5760 man-hours = 5760 ÷ 90 = 64 men.
Additional men to be employed = 64 − 20 = 44.
Check: 64 men × 9 hours/day × 10 days = 5760 man-hours, which matches the remaining work.