Find the time for two people working together to complete a task if it takes them 4.5 hrs and 6 hrs working individually.

Answer 1

1/x = 1/4.5 + 1/6

Solve that for x. The answer wil be in hours.

This assumes they work indepently on the same job. If they help each other and each does what he or she is best at, it might go faster. If they get in each other's way and fight, it will take longer.