Multiple choice

If A, B, C can finish a work in 18, 24, 36 days respectively. If they work for alternate days and A start the work then in how many days work will be finish?

  1. 24 days

  2. 36 days

  3. 20 days

  4. 18 days

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Work rates: A does 1/18 per day, B does 1/24 per day, C does 1/36 per day. In one 3-day cycle (A+B+C), they complete 1/18 + 1/24 + 1/36 = 4/72 + 3/72 + 2/72 = 9/72 = 1/8 of the work. So 8 cycles (24 days) are needed. Working 8 days each: A does 8/18, B does 8/24, C does 8/36. Total = 8/18 + 8/24 + 8/36 = 4/9 + 1/3 + 2/9 = 4/9 + 3/9 + 2/9 = 9/9 = 1 (complete).

Keep practicing — related questions