

1. 
If y varies inversely as x and y = 12 when x = 7, find x when y = 2. 


A. 
10 
B. 
5 


C. 
7 
D. 
42 


Hint 


2. 
If y varies inversely as the cube of x and y = 8 when x = 2, find x when y = 1. 


A. 
x = 8 
B. 
x = 1 


C. 
x = 4 
D. 
x = 2 


Hint 


3. 
If y varies jointly as x and the cube root of z, and y = 30 when x = 5 and z = 27, find y when z = 8 and x = 0.5. 


A. 
y = 20 
B. 
y = 2 


C. 
y = 4 
D. 
y = 2 


Hint 


4. 
Which best describes this graph? 





A. 
none of these 
B. 
inverse variation 


C. 
joint variation 
D. 
direct variation 


Hint 


5. 
Dakota wants to cook a meal for his family. He knows that the more people who help, the less time it will take to prepare the food. Write an equation that represents this situation. Let C be the cooks in the kitchen, T be the time and k as the constant of variation. 


A. 
k = C^{T} 
B. 
k = CT 


C. 
T = kC 
D. 
C = kT 


Hint 

