Direct and Inverse Practice

Which set of ordered pairs represent a direct variation?

• <(1,12), (2, 6), (3, 4), (4, 3)>

• <(1, 3), (2, 3), (3, 3), (4, 3)>

• <(1, 9), (2, 7), (3, 5)>

• <(4, 2), (6, 3), (8, 4), (10, 5)>

The number of hours to paint a house varies inversely with the number of painters working. A 2400-square foot house can be painted in 27 hours by 6 painters. How many painters would need to work in order to paint the house in 18 hours?

• 8 painters

• 10 painters

• 9 painters

• 11 painters

The time it takes to fly from Los Angeles to New York varies inversely as the speed of the plane. If the trip takes 6 hours at 900 km/h, how long would it take at 800 km/h?

• 5.33 hours 

• 6.75 hours 

• 12 hours 

• 10 hours 

Trina's paycheck earnings varies directly as the number of hours she works. If she works 19 hours and earns $187.15, what should she earn if she worked 40 hours?

• $394

• $443.25

• $472.80

• $512.20

What type of variation does this scenario represent?
The length of time you charge your cell phone
and the battery power 

• direct variation

• inverse variation

• joint variation

• none of these

What type of variation does this scenario represent?
The outside temperature
and the number of layers of clothes you need to wear outside to feel comfortable 

• direct variation

• inverse variation

• joint variation

• none of these

Which of the following represents indirect variation?

• y = kx

• y = k/x

• y = x/k

• y = mx + b

What kind of equation is this?
xy=8

• Linear Equation

• Direct Variation

• Inverse Variation

• Joint Variation

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

What type of variation does this scenario represent?
You and some friends decide to buy 2 pizzas and split the cost evenly.
The number of friends who are sharing the cost of the pizzas
and the amount of money you pay for your share.

• direct variation

• inverse variation

• joint variation

• none of these