A, B and C can do a work in 6, 8 and 12 hours respectively. If they work together, how many hours will they take to complete the work? MCQ with Answer and Explanation
A, B and C can do a work in 6, 8 and 12 hours respectively. If they work together, how many hours will they take to complete the work?
A. 2(2/3) hours
B. 2(1/2) hours
C. 3(1/3) hours
D. 3 hours
Answer: Option A
Solution (By JKSSB Mock Tests)
Total work = LCM(6, 8, 12) = 24 units. Efficiency of A = 4, B = 3, C = 2. Combined efficiency = 4 + 3 + 2 = 9. Time taken together = 24 / 9 = 8 / 3 = 2(2/3) hours.
Explanation:
Let efficiency of B = 5, then efficiency of A = 4. Total work = Efficiency of A * Time of A = 4 * 15 = 60 units. Time taken by B = 60 / 5 = 12 days.
No comments yet. Be the first to start the discussion!