t takes about 14 person-hours of labor to break up a driveway and clear away the rubble. It takes about 8 person-hours of labor to pour and smooth concrete for the new driveway. About how many person-hours of labor does it take to break up a driveway, clear away the rubble, pour the concrete, and smooth the concrete?  6

For this case what you must do is add the number of hours to perform the different activities.
 We have then:
 14 person-hours of labor to break up to driveway and clear away the rubble.
 8 person-hours of labor to pour and smooth concrete for the new driveway.
 Adding both activities we have
 14 + 8 = 22
 answer
 it takes to break up to driveway, clear away the rubble, pour the concrete, and smooth the concrete about 22 person-hours of labor