5.9 Direct and Inverse Practice

• direct variation
• inverse variation
• neither direct nor inverse variation

• direct variation
• inverse variation
• neither direct nor inverse variation

The equation 
xy =  25  represents:

• direct variation
• inverse variation
• joint variation
• none of these

Is the given table a direct variation? If so, what is the constant of variation?

• Yes; 1/3
• Yes; 3
• Yes; 5
• No

 Y varies directly with x, and y is 84 when x is 16. Which equation represents this situation?

• y=1344x
• y=100x
• y=5.25x
• y=4/21x

Which of the given graphs is a direct variation?

• A
• B
• C
• D

What kind of equation is this?
xy=8

• Linear Equation
• Direct Variation
• Inverse Variation
• Joint Variation

Is the given table a direct or inverse variation? What is the constant of variation?

• Direct, 12
• Inverse, 12
• Direct, 1/12
• Inverse, 1/12

Boyle’s Law states that, for a fixed amount of gas, the volume of the gas at a constant   temperature is inversely proportional to the pressure. If a certain gas occupies 9.84 liters   at a pressure of 50 centimeters of mercury (cm Hg), what is the approximate pressure   when the volume is increased to 12 liters?

• 39.8 cm Hg
• 41.0 cm Hg 
• 43.2 cm Hg
• 45.1 cm Hg

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