1 Find the constant of proportionality for the graph and write in the form y = kx.
a ( y = 5x)
b ( y = 3x)
c ( y = 15x)
d( y = 1/5 x)
2 The amount of money that Mary earns varies directly with the number of hours worked. If Mary earns $320 for working 40 hours, determine the constant of variation.
a 7
b 9
c 6
d 8
3 Given y varies directly as x, use the given x-value and y-value to find an equation that relates x and y.
x = 24 and y = 360
A x = 15xy
B y = 15x
C y = 15/x
D y = .15x
4 Length (x) Weight (y)
6 -------------15
9------------- 22.5
12----------- 30
15------------ 37.5
In her science classroom Jane noticed that the lengths (in inches) and the weights (in ounces) of the class's pet snakes were directly related by the equation y = kx, where x is the length and y is the weight. Use the information in the table to find k, the constant of proportionality.
A k = 2.5
B k = 1.5
C k = 2.0
D k = 3.0
5 The rate at which a plant grows is constant. At the 3rd week it is 12 inches tall and at the 5th week it is 20 inches tall. If this information is plotted on a coordinate plane, what is the y-coordinate of the point (1, y)?
A 1
B 2
C 4
D 9
6 Sarah is keeping up with how many miles her car gets per gallon. She starts with a full tank. After 448 miles, she fills up with 14 gallons. If she plots the points (0,0) and (14,448) on a coordinate plane, what would be the y-value of the point (1,y)?
A 26
B 32
C 16
D 28
7 Distance (miles) Time (hours)
7.5 1
15 2
22.5 3
30 4
Compare the graph of Car A to the table of Car B to determine which car is traveling at the greatest speed and by how much.
(A ) Car B is going 2 times faster than Car A
(B) Car B is going 3 times faster than Car A
(C) Car A is going 2 times faster than Car B
(D) Car A is going 3 times faster than Car B
11 (boxes of candy ) ( 10- 9- 2- 6- 3 )
( pieces of candy ) ( 150- 135 -30 -90 -45)
Find the constant of proportionality for the table and write in the form y = kx.
A y = 10x
B y = 1/15x
C y = 15x
D y = 150x
12 Eric made a graph of the distance (y), in miles, he can ride a bicycle in x hours. Eric can ride 6.5 miles in 0.5 hour. Which point on the graph represents Eric’s rate of travel, in miles per hour?
A (1, 13)
B (0, 6.5)
C (0, 13)(
D (1, 6.5)
13 Identify the constant of proportionality in the equation.
3y = 15x
A 1
B 3
C 5
D 10
14 Solve the equation for x.
14(2x + 8) = −16
A −24
B −18
C −36
D −28
15 Which equation represents a proportional relationship?
A y = 1/2x + 2
B y = 1/2x
C y = 1/2x + 1/2
D y = 1/2x + 1
10 answers
a) y = 5x: k = 5
b) y = 3x: k = 3
c) y = 15x: k = 15
d) y = 1/5x: k = 1/5
I hope that helps!