X can do a job in 16 days, and Y can do the same job in 20 days. X Y and Z can do the job in 7.5 days. Alone Z can do the same job in:
Q1. X can do a job in 16 days, and Y can do the same job in 20 days. X Y and Z can do the job in 7.5 days. Alone Z can do the same job in:
Answer: 48 days
Explanation: Combined rate of X and Y = 1/16 + 1/20 = 9/80 per day. Z's rate = 1/7.5 − 9/80 = 1/48 per day, so Z alone takes 48 days.