Sally can paint a room in 5 hours while it takes steve 7 hours. How long would it take them together?
1/7 + 1/5 = 1/x x is the time together
5/35 + 7/35 = 1/x
12/35 = 1/x
x = 35/12 = 2.92 hours = 2 hours 55 min
+36916 
