Direct Inverse and Joint Variation

What type of variation does this scenario represent?
The grade you earn in a class
and the number of assignments you complete
and the number of hours you study

• direct variation

• inverse variation

• joint variation

• none of these

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 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 equation 
xy =  25  represents:

• direct variation

• inverse variation

• joint variation

• none of these

State what type of variation the equation represents.

• Direct

• Inverse

• Joint

• None

State what type of variation the equation represents.

• Direct

• Inverse

• Joint

• None

HyVee found that the demand for Coke products varies inversely as the price of the product. When the price of a Coke product is $2.75, the weekly demand is 1250. Find the weekly demand if the price is raised to $4.00.

• 859.4

• 1818.2

• 1604.4

• 723.5

State what type of variation the equation represents.

• Direct

• Inverse

• Joint

• None

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 distance it takes to stop a car varies directly as the square of the speed of the car. If it takes 112 feet for a car traveling at 40 miles per hour to stop, what distance is required for a speed of 65 miles per hour?

• 308.05 ft

• 295.75 ft

• 296.09 ft

• 253.5 ft