Question

A thief escapes in a car driving at 60 km/h towards a city 400 km away. Only after 30 minutes, the police start to chase at 80 km/h. What distance will the police have covered when the thief is caught?

• A. 120 km
• B. 90 km
• C. 70 km
• D. 85 km

Answer 1

Answer:

A. 120 km

The thief has a 30-minute head start, which is equal to 0.5 hours. In that time, the thief covers a distance of 60 km/h * 0.5 h = 30 km. The police are chasing at 80 km/h, while the thief is driving at 60 km/h. The relative speed between them is 80 km/h - 60 km/h = 20 km/h. This is the speed at which the police are closing the gap. The police need to close the 30 km gap. Time = Distance / Speed = 30 km / 20 km/h = 1.5 hours. Distance = Speed * Time = 80 km/h * 1.5 h = 120 km.