Q. A and B together can complete a task in 10 days. B and C together can complete it in 15 days, and A and C in 12 days. In how many days can A alone complete the work?
✅ Correct Answer: (C)
20 days
Explanation: A+B = 1/10, B+C = 1/15, A+C = 1/12. Adding → 2(A+B+C) = 1/10 + 1/15 + 1/12 = 1/4 → A+B+C = 1/8. A = (A+B+C) - (B+C) = 1/8 - 1/15 = 1/20.
Explanation by: Kartik Sharma
A+B = 1/10, B+C = 1/15, A+C = 1/12. Adding → 2(A+B+C) = 1/10 + 1/15 + 1/12 = 1/4 → A+B+C = 1/8. A = (A+B+C) - (B+C) = 1/8 - 1/15 = 1/20.