P alone can complete a piece of work in 12 days, and Q can complete the same work in 18 days. With the help of R, all three finish the work in 6 days. In how many days can R alone complete the work?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 36 days.
LCM(12, 18, 6) = 36
The efficiency of P = 36/12 = 3 units
The efficiency of Q = 36/18 = 2 units
The efficiency of P + Q + R = 36/6 = 6 units
The efficiency of R = 6 - 5 = 1 unit
Time taken by R to complete the work alone = 36/1 = 36 days