In a practical problem, if a car travels 60 km/h and a truck travels 40 km/h, how long will it take for the car to catch up with the truck if the truck had a 30-minute head start?
Answer: B. 1.5 hours
Let t be the time in hours after the truck starts. The car travels 60t and the truck travels 40(t + 0.5). Setting these equal gives the solution t = 1.5 hours.