A runner times his speed around a circular track with a circumference of 0.478 mi. At the

Question:

A runner times his speed around a circular track with a circumference of 0.478 mi. At the start he is running toward the east and the track starts bending toward the north. If he goes halfway around, he will be running toward the west. He finds that he has run a distance of 0.750 mi in 4.00 min. What is his
(a) Average speed
(b) Average velocity in m/s?