A cat leaves a vacation spot traveling at 60 mph. Half and hour later, their friends leave from the same spot in a second car traveling at 75 mph. How long will it take the second car to catch up with their friends?

Time zero: cat leaves at 60 mph

Time 30 minutes: cat is 30 miles ahead, car leaves at speed=75 mph

Catch up speed = 75-60 = 15 mph (assuming cat does not run out of breath.)

Time to catch up = distance / speed = 30 / 15 = 2 hours.