Q. A alone can complete a work in 12 days. A and B together can complete it in 8 days. How long will B alone take to complete the work?
Answer: 24 days
Notes: A's one day's work $latex = \frac{1}{12}&s=1$ (A + B)'s one day's work $latex = \frac{1}{8}&s=1$ ∴ B's one day's work = $latex = \frac{1}{8} - \frac{1}{12} = \frac{3-2}{24} = \frac{1}{24}&s=1$ ∴ B alone can do the work in 24 days. Hence option [B] is the right answer

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