A can completes a work in 15 days and B in 25 days. A and B together work for 5 days. Then A goes for a leave of 5 days. When A returns then B leaves the work. For how many days A has to work alone to complete the whole work
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5 days
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6 days
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2 days
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8 days
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None of these
E
Correct answer
Explanation
Calculate A's rate = 1/15 per day and B's rate = 1/25 per day. Together they do 8/75 per day. In first 5 days (A+B): 5 × 8/75 = 8/15 work done. Next 5 days (B alone): 5 × 1/25 = 1/5 = 3/15 work done. Total done = 11/15, remaining = 4/15. A alone needs: (4/15) ÷ (1/15) = 4 days. Since 4 is not among options A-D, option E (None of these) is correct.