The graph represents the volume of water in a bath. The bath is full after 10 minutes. Work out the rate at which the bath is filled. State the units of your answer.

The rate at which the bath is filled is the gradient of the line on the graph. The gradient is calculated as the "rise" (change in vertical axis) divided by the "run" (change in horizontal axis). From the graph: - At time = 0 minutes, the volume is 0 litres. - At time = 10 minutes, the bath is full, and the volume is 240 litres. Change in volume (rise) = 240 - 0 = 240 litres. Change in time (run) = 10 - 0 = 10 minutes. Rate = Change in volume / Change in time Rate = 240 litres / 10 minutes Rate = 24 litres per minute. The units are taken from the axes labels: litres for the vertical axis and minutes for the horizontal axis.