A, B, and C can complete a work in 20, 30, and 60 days respectively. In how many days can they finish the work together?
Show answer & explanation
Correct answer: A
Explanation
A's work in 1 day = 1/20
B's work in 1 day = 1/30
C's work in 1 day = 1/60
Total work done by all three in 1 day = 1/20 + 1/30 + 1/60
= 3/60 + 2/60 + 1/60
= 6/60 = 1/10
This means that together, the three will complete 1/10 of the work in one day.
Therefore, the time taken to complete the entire work = 10 days.