Single correct option
A can complete a job in 12 days and B can complete the same job in 18 days. They work together for 4 days, after which A leaves. In how many more days will B alone finish the remaining work?
- A. 6
- B. 7
- C. 8
- D. 9
Show answer and solution
Answer: (C) 8
A's rate = 1/12, B's rate = 1/18. Combined rate for 4 days = 4×(1/12+1/18) = 4×(5/36) = 20/36 = 5/9 of the work done. Remaining work = 1 − 5/9 = 4/9. Days needed by B = (4/9)/(1/18) = (4/9)×18 = 8 days.
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