A certain number of persons can finish a task in 85 days. If there were 15 persons more, it would have taken 25 days less for the task to be completed. How many persons were there in the beginning?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 36.
Total work = x × 85
With x + 15 persons, the same work is done in 60 days:
⇒ ( x + 15 ) × 60 = x × 85
⇒ 60 ( x + 15) = 85x
⇒ 60x + 900 = 85x
⇒ 900 = 85x - 60x = 25x
⇒ x = = 36