A and B can do a project in 9 days. B and C can do it in 12 days while C and A can do it in 18 days. In how many days A, B and C all working together, can finish the project?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 8.
Given that
A and B can do a project in 9 days.
B and C can do it in 12 days
C and A can do it in 18 days
Total work = LCM (9, 12, 18) = 36
The combined efficiency of A and B = 36/9 = 4
The combined efficiency of B and C = 36/12 = 3
The combined efficiency of C and A = 36/18 = 2
The net efficiency of A + B + C = (4 + 3 + 2)/2 = 9/2
Hence, the total work will be completed by A, B, and C together in = 36/(9/2) = 8 days