P, Q and R can complete a task together in 15 days. P and R can complete the task together in 40 days. In how many days can Q complete the task alone?
Answer & explanation
Correct answer: option 2
P + Q + R = 15 days,
P + R = 40 days,
⇒ P + Q + R = 8
⇒ 3 + Q = 8
⇒ Q = 5,
Therefore, time required for Q to complete work alone = \(\frac{120}{5}\) = 24 days, ..(\(\frac{Work}{Efficiency}\) = Time)