A train makes a round trip on a straight, level track. The first half of the trip

Question:

A train makes a round trip on a straight, level track. The first half of the trip is 300 km and is traveled at a speed of 75 km/h. After a 0.50 h layover, the train returns the 300 km at a speed of 85 km/h. What is the train’s
(a) Average speed and
(b) Average velocity?