If 6 engineers can complete a work in 5 days and 5 skilled workers can complete the same work in 7 days, then the time taken (in days) to complete the same work by 7 engineers and 4 skilled workers will be:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. .
Engineers: 6 engineers complete the work in 5 days.
⇒ Work done by 1 engineer in 1 day = 1 / (6 × 5) = 1/30
Skilled workers: 5 skilled workers complete the work in 7 days.
⇒ Work done by 1 skilled worker in 1 day = 1 / (5 × 7) = 1/35
⇒ Work done by 7 engineers in 1 day = 7 × (1/30) = 7/30
⇒ Work done by 4 skilled workers in 1 day = 4 × (1/35) = 4/35
⇒ Total work done per day = (7/30) + (4/35) = (49/210) + (24/210) = 73/210
⇒ Time taken by 7 engineers and 4 skilled workers to complete the work = Total work / Work done per day = 1 / (73/210) = 210/73 days
Therefore, it will take 7 engineers and 4 skilled workers 210/73 days i.e. to complete the same work.