Direct, Inverse, Combined, Joint Variation

Suppose y varies directly as x, and y=39 when x=3.  Find the value of y when x=2.

• 26

• 3

• 58.5

• 2

Suppose y varies directly as x.
If  y = 22.5 when x = 15, find y when x = 20.

• 1.5

• 337.5

• 30

• 16.875

Suppose f varies directly as g, and f varies inversely as h.
f = -12 when h = 4 and g = -3.
Find g when f = 28 and h = 8.

• 14

• -14

• 16

• -16

Suppose y varies jointly as x & z. 
If y = -180 when z = 15
and x = -3,
then find y when x = 7 and z = -5.

• -140

• 140

• -4

• 4

The image is an example of the graph of a(n)

• direct variation

• inverse variation

• neither

• both

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

If x and y are in an inverse variation then which of the following is correct?

• x - y = constant

• x + y = constant

• xy = constant 

• x⁄y is constant 

Suppose y varies inversely with x.
If y = 150 when x = 2, find y when x = 25.

• 300

• 75

• 1,875

• 12

Suppose p varies directly as r, and p varies inversely as t.
t = 20 when p = 4 and r = 2.
Find t when r = 10 and p = -5.

• 80

• -80

• 4

• -20

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