Direct Variation

A dishwasher uses 65 gallons of water to wash 5 loads of dishes. What is the constant of variation?

• k = 13

• k = 65

• k = 5

• k = 1/13

If y vaires directly with x and y= 12 when x= 15. What is the value of x when y= 16?

• 12.8

• 20

• 11.25

• 19

if y is directly proportional to x, y is 10 when x is 3. What is the value of y when x is 5?

• 16 2/3

• 1.5

• 6

• 12

Is this proportional?
y=2x

• yes

• no

The amount of money earned on a job is directly proportional to the number of hours worked.  If $70.00 is earned in 5 hours, how much money is earned in 22 hours of work?

• $2

• $308

• $1.57

• $265

A person’s weekly pay is directly proportional to the number of hours worked. Shawn’s pay is $123.00 for 20 hours of work. Find the amount of pay for 31 hours of work. 

• $3813

• $620

• $190.65

• $4.96

The number of kilograms of water in a person’s body varies directly as the person’s mass.  A person with a mass of 90 kg contains 60 kg of water.  How many kilograms of water are in a person whose mass is 75 kg?

• 50 kg water

• 72 kg water

• 94 kg water

• 150 kg water

If y varies directly with x, and y = 0.66 when x = 8, what is y when x = 200?

• 16.5

• 2424.24

• -2424.24

• -16.5

If y varies directly with x, and y = 0.5 when x = -5, what is x when y = 3.5?

• -0.35

• 0.35

• 35

• -35

If y varies directly with x, and y = 32 when x = 64, what is x when y = 320?

• -160

• 160

• -640

• 640