Question
A can complete a work in 30 days, B in 24 days, and C in
20 days. A, B, and C work together for 5 days, after which B and C leave. How many more days will A take to complete the remaining work?Solution
Work done by A, B, and C together in 1 day = (1/30) + (1/24) + (1/20). LCM of 30, 24, and 20 is 120. Work done by A, B, and C in 1 day = (4 + 5 + 6)/120 = 15/120 = 1/8 of the total work. In 5 days, they complete 5/8 of the work. Remaining work = 1 − 5/8 = 3/8. A's rate of work = 1/30. Time taken by A to complete the remaining 3/8 of the work = (3/8) × 30 = 11.25 days. Ans. a
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