The answer is B
every hour, Steve and Carl cover 60 miles
if they need to cover 180 miles it will take them 3 hours
you can set up a proportion
60/1=180x where x is the amount of hours Steve and Carl will drive to cover 180 miles.
proportion simplifies to this:
60x=180
isolate the varible
60x/60=180/60
x=3
