Q. A and B together can do a piece of work in 12 days, while B alone can finish it in 30 days. A alone can finish the work in :
Answer: 20 days
Notes: A's 1 day's work $latex = \frac{1}{12}-\frac{1}{30} = \frac{5-2}{60} = \frac{3}{60} = \frac{1}{20}&s=1$ So, A alone will complete the work in 20 days. Hence option [C] is correct answer.

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