📢 Too many exams? Don’t know which one suits you best? Book Your Free Expert 👉 call Now!
  • google app store apple app store
    • ✖

      Question

      A, B, and C are hired to complete a task. A and B

      together can finish the work in 12 days, B and C together in 15 days, and A and C together in 20 days. How many days will it take for all three to complete the work together?
      A 8 days Correct Answer Incorrect Answer
      B 10 days Correct Answer Incorrect Answer
      C 12 days Correct Answer Incorrect Answer
      D 9 days Correct Answer Incorrect Answer
      E 7 days Correct Answer Incorrect Answer

      Solution

      Let the total work be 1 unit. Let A’s efficiency be a, B’s efficiency be b, and C’s efficiency be c. From the problem: 1/(A + B) = 1/12 1/(B + C) = 1/15 1/(A + C) = 1/20. To find 1/(A + B + C), = ½ {1/(A + B) + 1/(B + C) + 1/(A + C)} = ½ {1/12 + 1/15 + 1/20} = ½ { (5 + 4 + 3)/60 }= 12/120 = 1/10. This gives us the efficiency of (A + B + C) together, which is 1/10. Thus, all three together will take 10 days to complete the work. Final Answer: (b) 10 days

      Practice Next
      More Time and work Questions
      ask-question