Question
‘A’ and ‘B’ can do a piece of work in 20 days
and 30 days, respectively. If they started the work together and worked on it for 7 days, then find the time taken by ‘B’ alone to complete the remaining work.Solution
Let total amount of work be 60 units Efficiency of ‘A’ = 60/20 = 3 units/day Efficiency of ‘B’ = 60/30 = 2 units/day Amount of work done by ‘A’ and ‘B’ together in 7 days = (3 + 2) × 7 = 35 units Time taken by B to complete remaining work = (60 – 35)/2 = 12.5 days
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