A can complete a job in 10 days and B in 15 days. Working together, how many days will they take?
- A. 5 days
- B. 6 days
- C. 8 days
- D. 12 days
Explanation
Work with rates, not days. A does 1/10 of the job per day and B does 1/15. Together they do 1/10 + 1/15 = 3/30 + 2/30 = 5/30 = 1/6 per day, so the job takes 6 days.