DAY 227
I can paint a room in 8 hours and you can do it in 10. How long would it take us working together?

Answer:

4 4/9 hours..........I can do 1/8 of the job in one hour and you can do 1/10 of the job in one hour. 1/8 + 1/10 = 9/40. Together we can do 9/40 of the job in one hour. 9/40 divided into 1 = 4 4/9.