Question

$40$ men can complete a work in $40$ days. They started working together. But $5$ men kept on leaving the job every $10th$ day. In how many days work will be completed ?

• A. $45$ days
• B. $50$ days
• C. $55.5$ days
• D. $56.66$ days
• E. None of these

Answer 1

Answer: (D)

$56.66$ days

Total men days = 40 *40 = 1600 men days
40 men work in 10 days = 400 men days
35 men work in 10 days = 350 men days
30 men work in 10 days = 300 men days
25 men work in 10 days = 250 men days
20 men work in 10 days = 200 men days
Total men days till now = 400 + 350 + 300 + 250 + 200 = 1500 men days
Rest men days = 1600 - 1500 = 100 men days
Now, 15 men will work for complete 100 men days in = 100/15 = 6.66 days
So total days = 10 *5 + 6.66 = 56.66 days.