If A and B can finish a work in 10 days, B and C can finish the same work in 12 days, C and A can finish the same work in 15 days; then in how many days can A, B and C together finish half of the work?

  1. A. 8 days
  2. B. 5 days
  3. C. 4 days
  4. D. 3 days

Correct Answer: C. 4 days

Explanation

Let total work be LCM(10, 12, 15) = 60 units. Efficiencies: A+B=6, B+C=5, C+A=4. Summing gives 2(A+B+C) = 15 \implies A+B+C = 7.5 units/day. Time for half work (30 units) = \frac{30}{7.5} = 4 days.

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