A can complete a task in 15 days, and B can complete the same task in 20 days. How long will it take them to complete the task together?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 8.5 days.
A's rate = 1/15
B's rate = 1/20
Combined rate = 1/15 + 1/20 = 7/60
Time required = 1 ÷ (7/60) = 60/7 days = 8.57 days ≈ 8.5 days