Multiple choice

A can do a piece of work in 12 days, B can do it in 15 days and C can do it in 20 days. They together can do the whole work in

  1. 5 days

  2. 4 days

  3. 8 days

  4. 10 days
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A's one-day work = 1/12, B's one-day work = 1/15, C's one-day work = 1/20. Combined work per day = 1/12 + 1/15 + 1/20. LCM of 12, 15, 20 is 60. So, 5/60 + 4/60 + 3/60 = 12/60 = 1/5. Therefore, together they complete the work in 5 days.

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