Q. Raj and Ram working together do a piece of work in 10 days. Raj alone can do it in 12 days. Ram alone will do the work in :
Answer: 60 days
Notes: (Raj + Ram)'s 1 day's work $latex = \frac{1}{10}&s=1$ Raj's 1 day's work $latex = \frac{1}{12}&s=1$ ∴ Ram's 1 day's work $latex =\frac{1}{10}-\frac{1}{12} = \frac{6-5}{60} = \frac{1}{60}&s=1$ ∴ Required Time = 60 days. Hence option [D] is correct answer.

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