Answer: Hello there!
We know that paul can install a 300 ft^2 floor in 18 hours.
Then he can install 300/18 = 16.67 ft^2 floor per hour.
Matt can install the same floor in 22 hours, then in one hour he can do:
300/22 = 13.64 ft^2 per hour.
if they work together, they can install (16.67 ft^2 + 13.64ft^2) = 30.3 ft^2 per hour.
now we want to see how much time they need to install the 300 ft^2 floor at a rate of 30.3 ft^2 per hour:
this is 300/30.3 = 9.9 hours or 9 hours and 54 minutes.
