Direct Variation

 y varies directly with x, and y is 84 when x is 16. What is the constant of proportionality?

• y = (21/4)x
• k= 21
• k= 5.25
• k= 4/21

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

In a direct variation, y=39 when x=3.  Find the value of y when x=2.

• 26
• 3
• 58.5
• 2

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
• $440
• $472.80
• $512.20

The value of y varies directly with x. If x=3, then y=21. What is the value of x when y=105?

• 3/5

• 1 2/3

• 7

• 15

In an electrical circuit, the voltage across a resistor is directly proportional to the current running through the resistor. If a current of 12 amps produces 480 volts across a resistor, how many volts would a current of 1.5 amps produce across an identical resistor?

• 60

• 3,840

• 8

• 320

Roger works at a flower shop and he notices that the more flowers people buy, the more chocolates are sold too. If Roger sells 45 chocolates when 90 flowers are sold, how many chocolates does he sell if 100 flowers are sold?

• 90

• 70

• 50

• 30

A soap manufacturing company packs 52 soaps per carton. Find the number of soaps that can be packed in 10 cartons if the number of soaps packaged is directly proportional to the number of cartons.

• 468

• 624

• 572

• 520

A car runs 18 mi. on 2 gallons of gas. The number of gallons of gas varies directly with the number of miles the car runs. How many miles will the car run on 4.4 gallons of gas?

• 39.6 mi.

• 2 mi.

• 9 mi.

• 18 mi.

Alyssa is going to save money for a new car. She opens a brand new bank account. She deposits $35 each week. After 6 weeks, she has $210. If y varies directly with x, how much money will she have saved after 1 year? (52 weeks)

• $10,920

• $1,820

• $210

• $1,885