Question: A can do a piece of work in 10 days, B in 12 days & C in 15 days. All being together but A leaves the work after 2 days and B leaves 3 days before the work is finished. How long did the work last? . . .

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Question: A can do a piece of work in 10 days, B in 18 days, & A, B & C together in 4 days. In what time would C alone do it? . . .