ANSWER
Paul and Matt will take

to install the floor working together.
Step-by-step explanation
First, calculate Paul's rate, which is

Next, calculate Matt's rate, which is,

Let us assume that, Paul and Matt took

to do the work together.
Then, the rate of working together is,

Now, add the individual rates and equate to the rate of working together to form an equation that will help us solve for x.

Simplify the left hand side


We reciprocate both sides to get (You could have also done cross multiplication).

