+ 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)

The sum of two numbers is 12 and their difference is 18 what are the two numbers

The figure below shows rectangle abcd and the triangle eca on a coordinate plane.which of the following expressions represents the perimeter of triangle of triangle eca in units

An automobile assembly line operation has a scheduled mean completion time, μ, of 12 minutes. the standard deviation of completion times is 1.6 minutes. it is claimed that, under new management, the mean completion time has decreased. to test this claim, a random sample of 33 completion times under new management was taken. the sample had a mean of 11.2 minutes. assume that the population is normally distributed. can we support, at the 0.05 level of significance, the claim that the mean completion time has decreased under new management? assume that the standard deviation of completion times has not changed.