Inverse Variation and Rational Functions

Given that y varies inversely with x, if x =7 and y = 4, what is y when x = 2?

• 14
• 10
• 2
• -14

Does the equation show an inverse variation? 
y=10/x

• yes
• no

What kind of variation does this equation show?
y = 6x

• Inverse Variation
• Direct Variation
• No Variation
• Joint Variation

Given the following equation, identify the constant k.
y = 54/x

• There is one.
• k = x
• 54
• y = k

If y varies jointly with the product of x and z, and y = 105 when x = 5 and z = 7, find y when x = 9 and z = 10.

• 270

• 180

• 360

• 255

The variable x is in joint variation with y and z. When the values of y and z are 4 and 6, x is 16. What is the value of x when y = 8 and z =12?

• 32

• 64

• 48

• 96

A is in joint variation with B and square of C. When A = 144, B = 4 and C = 3. Then what is the value of A when B = 6 and C = 4?

• 12

• 24

• 36

• 48

The equation for a Joint Variation is represented as:

• y = kx

• y = k/x

• y = kxz

• y = kx/z

The weight of a liquid varies directly as its volume V. If the weight of the liquid in a cubical container 5 cm on a side is 250 g, find the weight of the liquid in a cubical container 3 cm on a side.

• 12 g

• 6 g

• 27 g

• 54 g

The volume of wood in a tree varies jointly as the height of the tree and the square of the distance around the tree trunk. If the volume of wood is 15.84 cubic feet when the height is 22 feet and the distance around the trunk is 3 feet, what is the volume of wood obtained from a tree that is 32 feet tall having a measurement of 4 feet around the trunk?

• 44.96 ft³

• 49.96 ft³

• 40.96 ft³

• 32.96 ft³