If A and B together can complete a job in 15 days and B alone can complete it in 20 days, in how many days can A alone complete the job?
Q1. If A and B together can complete a job in 15 days and B alone can complete it in 20 days, in how many days can A alone complete the job?
Answer: 60 days
Explanation: A's rate = 1/15 − 1/20 = 1/60 of the job per day; A alone takes 60 days.