A, B and C can do a work in 36, 72 and 54 days respectively. They started the work together but A left 8 days before the completion of the work and C left 12 days before the completion of the work. In how many days was the work completed?
A, B and C can do a work in 36, 72 and 54 days respectively. They started the work together but A left 8 days before the completion of the work and C left 12 days before the completion of the work. In how many days was the work completed? Correct Answer 24
Given:
A, B and C can do a work in 36, 72 and 54 days respectively.
A left 8 days before the completion of the work.
C left 12 days before the completion of the work.
Formula used:
Work = Time × Efficiency
Calculation:
Efficiency of A = 1/36
Efficiency of B = 1/72
Efficiency of C = 1/54
Suppose work is completed in d days.
Work done by A = (d - 8)/36
Work done by B = d/72
Work done by C = (d - 12)/54
Total work done by A, B and C = (d - 8)/36 + d/72 + (d - 12)/54
(6d - 48 + 3d + 4d - 48)/216 = 1
⇒ 13d = 216 + 96 = 312
⇒ d = 24 days
∴ Required number of days = 24 days
Alternate Solution:
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Work done by A in 8 days = 6 × 8 = 48
Work done by C in 12 days = 12 × 4 = 48
Work done = 216 + 48 + 48 = 312
∴ Required number of days = 312/13 = 24 days