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A, B and C can do a work in 10, 20 and 30 days respectively. Find the time work will be finished in if B is assisted by A on every alternate day and by C on every third day.1. 25/32. 26/33. 28/34. 31/3 |
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Answer» Correct Answer - Option 3 : 28/3 Given: A, B and C can do a work in 10, 20 and 30 days respectively. Formula Used: If A and B can together finish a work in t days and alone can finish the work in a and b days respectively, Then, 1/a + 1/b = 1/t Work = Time × Efficiency Calculation: Total work = LCM of 10, 20, 30 = 60 units Efficiency of A = 6 Efficiency of B = 3 Efficiency of C = 2 1 2 3 4 5 6 7 8 9 10 (Days) B BA BC BA B ABC B AB BC AB 3 9 5 9 3 11 3 9 5 9 57 units can be completed in 9 days. Remaining work = (60 – 57) units = 3 units On 10th day 9 units will be done Remaining 3 units will be done in = 3/9 days = 1/3 days Total work will be done in = (9 + 1/3) days = 28/3 days ∴ The work will be finished in 28/3 days. |
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