Math III - Variations Practice

 Y varies inversely with x, and y is 0.5 when x is 4. Which equation represents this situation?

• y=2x
• y=2/x
• y=4x
• y=x/2

The equation 
xy =  25  represents:

• direct variation
• inverse variation
• Neither

Assume y varies inversely with x. If x=7 when y=4, what is y when x=2 ?

• 4
• 14 
• 7
• 28

Which of the following represents direct variation?

• y = kx
• y = k/x
• y = x/k
• y = mx + b

a varies inversely as the square of b. If a is 1 when b is 3, find a when b is 5. 

• 0.36
• 9
• 25
• 36

What is the constant (k) in this inverse variation?
y = 400/x

• x
• y
• 400
• Not enough information given

In a direct variation, y=39 when x=3.  Find the value of y when x=2.

• 26
• 3
• 58.5
• 2

y varies jointly as x and z

• y=kx/z

• y=kxz

• y=kz/x

• y=k+x+z

y varies inversely as x

• y=kx

• y=k/x

• y=k+x

• y=k-x

Suppose a varies jointly as b & c. 
If a = 15 when b = 4
and c = 5,
then find b when a = 60 and c = 5.

• 320
• 225
• 16
• 8