A can do a job in 18 days and B in 36 days. They work together for 4 days, and then A leaves. In how many more days will B finish the job?

💡 Solution & Explanation

Together they do 1/18 + 1/36 = 1/12 of the job per day, so in 4 days they finish 1/3 of it. The part left is 2/3 of the job. B alone does 1/36 of the job per day, so B needs 2/3 × 36 = 24 more days.