Multiple choice

A, B and C can do a piece of work in 30 days, 45 days and 90 days respectively. A starts the work and he is assisted by B and C together on every third day. In how many days will the work be completed?

  1. 23

  2. 24

  3. 30

  4. 22.5
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Work pattern repeats every 3 days: Days 1-2 only A works (1/30 each), Day 3 all three work together (1/30+1/45+1/90=6/90=1/15). Every 3-day cycle completes 2/30+1/15=2/15 of work. For 23 days (7 cycles + 2 days): 7*(2/15)=14/15 plus 2/30=1/15 gives total 15/15=1.

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