tina can paint a room in 8 hours, but when she and her friend emily work together, they can complete the job in 3 hours. how long would it take emily to paint the room alone?

Answer 1

Tina can paint 1/8 of a room in one hour.
Tina and Emily can paint 1/3 of a room in one hour.
So Emily can paint (1/3-1/8)=5/24 of a room in one hour.
It therefore takes Emily 1/(5/24)=24/5 hours to paint a room

Answer 2

4.8 hours