Linear System Word Problems

Jerry has $20 and makes $7 per hour. Which equation represents the total amount of money Jerry has after working x hours?

• y = 7x + 20

• y = 7 + 20x

• y = 20 + 7

A boy has seven more nickels than quarters. The total value of the coins is $4.90. Which system could be used to find out how many nickels and quarters he has?

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On Monday Joe bought 10 cups of coffee and 5 doughnuts for his office at the cost of $16.50. It turns out that the doughnuts were more popular than the coffee. On Tuesday he bought 5 cups of coffee and 10 doughnuts for a total of $14.25. Which equations could be used to determine the cost of the coffee?

• 10c + 5d = 14.25
  5c + 10d = 16.50

• 10c + 5d = 16.50
  5c + 10d = 14.25

• c + d = 10
  5c + 10d = 16.50

• c + d = 5
  5c + 10d = 16.50

David is running a concession stand at a soccer game. He sells nachos and sodas. Nachos cost $1.50 each and sodas cost $0.50 each. At the end of the game, David made a total of $78.50 and sold a total of 87 nachos and sodas combined. 

• 35 nachos, 52 sodas

• 18 nachos, 69 sodas

• 52 nachos, 35 sodas

• 61 nachos, 26 sodas

A man is climbing down from 100 feet high descending 30 feet per minute.

• y = 100 - 30x

• y = 100 + 30x

• y = 100x + 30

• y = 100x - 30

Bob has $150 in his savings account and saves $40 per month.  Which equation represents the amount Bob has in his account after x months?

• y = 150 + 40

• y = 40x + 150

• y = 150x + 40

The Roaming Cell Phone Company charges $15.00 per month plus $0.20 per minute of airtime usage.  If Juanita uses x minutes of airtime, what is an equation that can be used to determine her monthly cell phone bill (C)?

• C = 0.20x + 15

• C =15 (0.20x)

• C = 15 + x + 0.20

• C = 0.20 + 15x

Write the linear inequality in standard form for this situation: Ms. Savva is ordering pizzas and breadsticks for a school party and has a budget of no more than $81. An order of breadsticks costs $7 and a pizza costs $13. 

• 7x + 13y < 81

• 7x + 13y ≥ 81

• 7x + 13y ≤ 81

• 7x + 13y > 81

Write the linear inequality in standard form for this situation: In order to raise money to attend upcoming competitions, the Math Pentathalon team is selling apple cider and hot chocolate. They hope to make at least $240 by selling hot chocolate for $1 a glass and hot apple cider for $2 a glass.

• x + 2y < 240

• x + 2y > 240

• x + 2y ≤ 240

• x + 2y ≥ 240

Write the linear inequality in standard form for this situation: The manager of an electronics store projects that the store should achieve more than $21,000 in revenue from TVs and DVD players every day in order to remain profitable. Tvs sell for $225 and DVD players sell for $175.

• 225x +175y ≤ 21,000

• 225x +175y ≥ 21,000

• 225x +175y < 21,000

• 225x +175y > 21,000