## Rates Exercise

1. (a) A car travels from city A to city B, a distance of 360 km, in 5 hours. What is its average speed?

(b) The car uses 30 litres of fuel. What was its fuel consumption in km/litre?

2. Express each rate in its simplest form in the units given:

(a) 50 km in 5 hours in km/h

(b) 300 revolutions in 1 hour in revs/min

(c) 20 g per 5 cmin g/cm3

3. The table shows the level of water in a water tank at different times as it is being drained at a constant rate.

The water is 50 cm deep at the start.

 Time (hours) Level (cm) 0 50 1 40 2 30 3 20 4 10 5 0

(a) Use the table to find the rate at which the water level is falling.

(b) Sketch a graph to show this data, with time along the horizontal axis.

(c) What is the gradient of the line?

4. The table shows the relationship between the area and the radius of a circle.
The formula connecting them is A = . ( is given an approximate value of 3 in the table.)

 Radius (r) Area (A) 0 0 1 3 2 3 4

(a) Complete the table.

(b) Sketch a graph to show this data.

(c) Describe in words what is happening to the area of the circle as the radius increases.