Question
‘E’ alone completes a task in 28 days. ‘F’ is
10% less efficient than ‘E’. They worked together for 7 days and then ‘E’ stopped. What percentage of the task was completed by ‘F’?Solution
ATQ,
Given: E completes work in 28 days → E's rate = 10 units/day  F is 10% less efficient → F's rate = 9 units/day  Total work = 280 units  Work done in 7 days by E and F: (10 + 9) × 7 = 133 units  Remaining work = 280 - 133 = 147 units F works alone after that: Time = 147 ÷ 9 = 16.33 days  F alone did 147 units out of 280  Hence, F alone did (147/280) × 100 = 52.5% of the work
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