30 men working 5 hours a day can do work in 18 days. In how many days will 20 men working 7 hours a day do the same work?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 19.
Let the required number of days be x
Total work = M × D × H
here, M = Mens, D = Days, H = Hours
Total work = 30 × 5 × 18 = 2700
Now,
Time taken by 20 men working 7 hours a day
⇒ 2700 = 20 × 7 × x
⇒ 140x = 2700
⇒ x = 270/14 = 135/7 = 19