One third of the candidates for a job were 25 years old or younger. Two sevenths of the candidates were at least 50 years old.
**If 84 people applied for the job, how many were between 25 and 50?**

32

28

24

33

**Which of the following is a factor of 450 and multiple of 25?**

30

75

90

100

The formula h - 15 = 3.2t gives the height h in inches of a plant t weeks after planting.
**Which is the rate at which the plant's height is increasing?**

15 inches per week

18.2 inches per week

3.2 inches per week

48 inches per week

**How high was the initial height of the shrub?**

15 inches

3.2 inches

18.2 inches

11.8 inches

The formula h -15 = 3.2t gives the height h in inches of a plant t weeks after planting.
**When was the height 31 inches?**

Some time between 11 and 18 weeks

Some time between 7 and 12 weeks

Some time between 6 and 10 weeks

Some time between 3 and 7 weeks

3.2t = 16

t = 16÷3.2

t = 5

The height is 31 inches after 5 weeks

The next three questions refer to the following diagram:

A graph of the temperature T (degrees Fahrenheit) in a refrigerator t hours after midday.
**What is the equation of the axis of symmetry of this graph?**

T = 9

t = 3

T = 0

t = 0

Refer to the following diagram:
**It is necessary to find the times when the temperature is 8o F. Which of the following is the correct equation to do this.**

9 - t = 8

9 +t^{2} = 8

9 - t^{2} = 8

9t - t^{2} = 8

**Which of the following is the equation of the straight line joining the points on the graph corresponding to t = 2 and t = 1?**

T + 3t = 11

T - 3t = 11

T + 11t = 3

T + 3t = 1

The point on the graph corresponding to t = 2 is (2,5).

The slope of the straight line joining them is (5 - 8)÷(2 - 1) = -3.

The equation is T = -3t + c

As (2,5) lies the line we can substitute for t and T.

5 = -3×2 + c

c = 11

Equation is T = -3t + 11 which is the same as (a)

The following two questions relate to the sphere shown below:

The formula for the volume V of the sphere = 4(pi)r^{3} / 3.
**Which of the following is the closest approximation to the volume when r, the radius, is 11 inches?**

6000 cubic inches

5590 cubic inches

5573 cubic inches

5000 cubic inches

**If the radius of the sphere were doubled by what factor would the surface area be enlarged**?

Note: The formula for the surface area S of the sphere = 4 x (pi) x r^{2}

2

4

8

16