Question

If, on their own, it takes 6 hours for Person A to complete a task and 9 hours for Person B to complete the same task, then how many hours would it take if they worked together? Estimate your answer to 4 places after the decimal, if necessary.

Answer 1

Explanation:

A does 1/6 of the task per hour.

B does 1/9 of the task per hour.

Together, they do 1/6+1/9 = 5/18 of the task per hour, finishing in 18/5 hours.

18/5 = 3.6 hours