From the information given, speed of the car is 90km/hr and that of the truck is 50km/hr The difference in velocity is (90 - 50)km/hr = 40 km/hr 40 Km = 40, 000 m 60 minutes =40, 000m 1 min = ? 1 min = 40,000 / 60 = 666.7 m The car covers 666.7 m in one minute, how about 100 m? 1min = 666.7m ? = 100m → 666.7/ 100 = 0.15 The car will take 0.15 minutes or 9 seconds to reach the truck.