Time and Distance - General Questions

A car travels from A to B at 60 km/hr and returns from B to A at 90 km/hr. What is the average speed for the whole journey?

A car travels from A to B at 20 km/hr and returns from B to A at 30 km/hr. What is the average speed for the whole journey?

Walking at 5/6 of his usual speed, a man is 8 minutes late. What is his usual time to cover the distance?

How far does a cyclist travel in 36 minutes at a speed of 45 km/hr?

How far does a cyclist travel in 30 minutes at a speed of 40 km/hr?