An odometer in a car has a reading of 50 km at the beginning of a trip and a reading of 125 km half an hour later. What is the average speed of the car?

Textbook ans: 150km/h

Please can someone help me solve this problem? I don't know how to solve it. Can you show me steps (formula).

Thanks.

distance = 125-50 = 75 km

time = 0.5 hr

distance/time = 75 km / .5 hr = 150 km/hr