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1. A can do 3 piece of work in 4 hours, B and C together in 3 hours , and A and C together in 2 hours. How long will B alone take to do it?
- A. 8 hours
- B. 8 hours
- C. 8 hours
- D. 8 hours
Answer: Option B
Explanation:
A,B and C together need = (3×4)/(3 + 4) = 12/7 hours
And C need 2 hours
∴B need = {(12/7)×2}/{2 - (12/7)} hours
= (24/7)/{(14 - 12)/7}
= 24/2 hours
= 12 hours
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