A started a work such that he can complete the whole work in 30 hours. After working for 10 hours, he worked with the rate such that the whole work can be completed in 24 hours. In how many hours A can complete the whole work?
Let the total work = 120 units Efficiency of A when he can complete the whole work in 30 hours = 120/30 = 4 units/hour Efficiency of A when he can complete the whole work in 24 hours = 120/24 = 5 units/hour Amount of work done in 10 hours = 10 × 4 = 40 units Time taken to complete the remaining work = (120 – 40)/5 = 16 hours Therefore, total time taken = 16 + 10 = 26 hours
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