Question 890108
Working alone, Sue can paint a 10' x 12' rectangular room in 12 hours.  Joe can paint the same room in 16 hours.  If they work together, how long will it take them to paint the room?
.
Let x = time together
then
x(1/12 + 1/16) = 1
x(16 + 12) = 192
x(28) = 192
x = 6.857 hours
or
x = 6 hours and 51 minutes