Multiple choice

A,B and C can complete a work in 20, 24 and 30 days respectively. All three of them starts together but after 4 days B leaves the job in how many days the total work will be completed?

  1. 10

  2. 12

  3. 15

  4. 18
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

LCM of 20, 24, 30 is 120 units. A's rate=6 units/day, B's rate=5 units/day, C's rate=4 units/day. First 4 days: all work together at 15 units/day → 60 units done. Remaining 60 units done by A+C at 10 units/day → 6 more days. The question asks total time, which is 4+6=10 days. Option A is correct.

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