Question

Rachael paints a room in 9 hours, Kelsey paints the same room in 15 hours Working together they can paint this room in how many hours

Answer 1

Rachael paints a room in 9 hours, so her work rate is 1/9 of work per hour.

Kelsey paints the same room in 15 hours, so her work rate is 1/15 of work per hour.

Together, their combined work rate is

`(1)/(9)+(1)/(15)=(8)/(45)`

Which means it will take them 45/8 of a hour to complete the job together.