Rate and speed：练习题

A train travels a distance of \( 180\text{ km} \) in \( 2.5\text{ hours} \). Calculate its average speed in \( \text{km/h} \).

A car travels the first \( 60\text{ km} \) of a journey at an average speed of \( 40\text{ km/h} \) and the remaining \( 120\text{ km} \) at an average speed of \( 80\text{ km/h} \). Find the average speed of the car for the entire journey.

A train travels a distance of \( d \text{ km} \) at an average speed of \( v \text{ km/h} \). If the speed is increased by \( 10 \text{ km/h} \), the time taken for the journey is reduced by 2 hours. Write down an equation in terms of \( d \), \( v \) and the time reduction.

An object is moving at a constant speed of \( 72\text{ km/h} \). What is its speed in \( \text{m/s} \)?

An athlete runs \(1,500 \text{ metres}\) in \(4 \text{ minutes}\) and \(10 \text{ seconds}\). Calculate the average speed of the athlete in \(\text{m/s}\).

A cyclist travels at a constant speed of \( 15 \text{ m/s} \). Calculate the distance, in kilometres, the cyclist covers in \( 1.5 \) hours.

A delivery van travels from Warehouse A to Warehouse B, a distance of \( 45 \) km, at an average speed of \( 60 \) km/h. It then travels from Warehouse B to Warehouse C at an average speed of \( 40 \) km/h for \( 45 \) minutes.
(a) Calculate the total distance traveled from Warehouse A to Warehouse C.
(b) Calculate the average speed of the van for the entire journey from A to C, giving your answer in m/s.