A can complete a job in 15 days and B in 20 days. They work together for 5 days. How much work is left?
Show answer & explanation
Correct answer: B
Explanation
Given:
A does the work in 15 days
B does the work in 20 days
They both work together for 5 days
A's rate = 1/15
B's rate = 1/20
Together's rate = 1/15 + 1/20 = 7/60
Work done in 5 days = 5 × 7/60 = 7/12
Remaining work = 1 − 7/12 = 5/12