The efficiencies of A, B and C are in the ratio 5 : 3 : 8. Working together they can complete a work in 30 days. A and B worked together for 20 days. The remaining work will be completed by C alone in:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e 40 days
Total work = Efficiency × Time
Ratio of efficiencies of A, B and C = 5 : 3 : 8
Suppose the efficiencies are 5x, 3x and 8x
Working together, they can complete task in 30 days:
Total work = (5x + 3x + 8x) × 30 = 480x
Work completed by A and B together in 20 days = (5x + 3x) × 20 = 160x
Remaining work = 480x – 160x = 320x
Time in which C will complete remaining work = 320x/8x = 40 days