A can do a work in 10 days and B in 15 days. They work together for 3 days and then A leaves. How long will B take to finish the rest?
A5 days
B7.5 days
C8.5 days
D10 days
Explanation
A+B=1/10+1/15=1/6. In 3 days, they do 3/6=1/2. Remaining=1/2. B does 1/2 in (1/2)/(1/15) = 7.5 days.
Exam Relevance
- Topic: Work and Time
- Subtopic: Work Completion
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