ACT SAT Prep Learn how to combine rates of two people to determine one individual rate

The video tutorial explains how to calculate the time it takes for two people, Joseph and Mitch, to install a driveway together at their individual rates. Joseph can complete a driveway in 9 hours, while Mitch takes 18 hours. By working together, they can complete a driveway in 6 hours. The tutorial uses an example of 36 hours to demonstrate how many driveways they can complete together, showing that Joseph can do 4 and Mitch can do 2, totaling 6 driveways. The conclusion is that together, they can complete one driveway in 6 hours.

If they worked together for 36 hours, how many driveways could they complete?

How many hours would it take for Joseph and Mitch to complete one driveway together?