A and B can do a piece of work in 45 days and 40 days, respectively. They began to do the work together but A left after some days and then B completed the remaining work in 23 days. The number of days after which A left the work, is?
Correct Answer: 9 days
Explanation:
By the fundamental of work and time,
x/45 + (x + 23)/40 = 1
⇒ x = 9 days
