A can compete of the work in 9 days and B can complete of the work in 6 days. Working together, A and B can complete of the work in ___________.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 6 days.
Let total work = 5 units (LCM of denominators 5 and 5)
3/5 of work = 3 units in 9 days ⇒ A’s 1 day work = 3/9 = 1/3 units
So, total capacity of A : 1/3 × 5 = 5/3 units in total work
1/5 of work = 1unit in 6 days ⇒ B’s 1 day work =1/6 units
So, total capacity of B : 1/6 × 5 = 5 /6 units in total work
Together per day: 1/3 + 1/6 = 2/6 + 1/6 = 3/6 = 1/2 units per day
To complete 3/5 of work = 3 units:
3 ÷ 1/2 = 3 × 2 = 6 days