Direct and Inverse Variations

The Height of a wave in California varies directly with the seconds that pass by.  At 4 seconds, the wave is 6 feet high.  How many seconds will give you a wave that is 10 feet high? 

• y = 2/3x

• 6

• 6.6

• 7

The sales at a baseball game vary directly with the number of people attending.  If sales for a game are $12,000 when 800 people attend, determine attendance if sales are $30,000

• 1200 people

• 1500 people

• 2000 people

• 2400 people

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

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

The gas pressure in a chamber varies directly with the temperature in the chamber. If the pressure in the chamber is 150 atmospheres (atm) when the chamber is at 50 degrees, what is the pressure in the chamber when the temperature of the chamber is 75 degrees? 

• 175 atm

• 200 atm

• 225 atm

• 275 atm

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

State what type of variation the equation represents.

• Direct

• Inverse

• Joint

• None

If x varies inversely as v, and x = 35 when v = 3, find x when v = 15.

• 7

• 9

• 5

• 21

The time required to process a shipment of goods at Wal-Mart varies directly with the number of items in the shipment and inversely with the number of workers assigned. If 15,000 items can be processed by 8 workers in 10 hours, then how long would it take 12 workers to process 20,000 items?

• 6.5 hours

• 7.75 hours

• 8.9 hours

• 10.2 hours

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