Two towns are 165 km apart. A car and a bus start travelling towards each other from their respective towns. The car moves 10 km/h faster than the bus. If they pass each other in 1.5 hours after they began their respective journeys, find the speed of each vehicle.

I'm guessing I have to use the formula:

average speed = (distance travelled)/(time taken)

But I'm not sure...well any help on the above will be appreciated!