+ A (litres) 160
140
120
100
The amount of oil A left in a leaky barrel after
t minutes is shown on the graph alongside.
a Find the gradient and A-intercept of the line.
Interpret your answers.
b Find the model connecting A and t.
< How much oil will be left after 15 minutes?
d For what values of t is it reasonable to apply
this model?
80
60
40
20
0
0
2
4
6 8
t(minutes)