A and B can do a work in 10 and 15 days, respectively. If they work together, how many days will they take to complete it?
Q1. A and B can do a work in 10 and 15 days, respectively. If they work together, how many days will they take to complete it?
Answer: 6 days
Explanation: A's rate is 1 / 10, B's rate is 1 / 15. Together, their rate is 1 / 10 + 1 / 15 = (3 + 2) / 30 = 5 / 30 = 1 / 6. So, they will take 6 days.