Question
'Aman' and 'Bhanu' together can complete a work in 7.2
days. Both of them started the work but 'Bhanu' left the work after 3 days and remaining work was completed by 'Aman' alone in 7 days. Efficiency of 'Charu' is 50% more than the efficiency of 'Bhanu'. Find the time taken by 'Charu' to complete 80% of the workSolution
ATQ, Let the efficiency of 'Aman', 'Bhanu' and 'Charu' be 'p' units/day, 'q' units/day and 'r' units/day respectively. Total work = 7.2(p + q) units Work completed by 'Aman' and 'Bhanu' in 3 days = 3(p + q) units ATQ: 3(p + q) + 7p = 7.2(p + q) Or, 3p + 3q + 7p = 7.2p + 7.2q Or, 2.8p = 4.2q So, p:q = 3:2 Let 'p' = 3k and 'q' = 2k So, 'r' = 1.5 X 2k = 3k So, required time = [7.2 X (3k + 2k) X 0.80] ÷ 3k = 9.6 days
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