Application of Systems of Equations

Erin is 3 years younger than twice Alex's age. Their ages combined are 33 years. Choose the system that can be used to determine Erin and Alex's age.

• x + y = 33
  y = 2x - 3

• x + y = 33
  x = 2y - 3

• x + y = 33
  x = 3 - 2y

• x + y = 3
  x = 33 - 2y

Some students want to order shirts with their school logo. One company charges $9.65 per shirt plus a setup fee of $43. Another company charges $8.40 per shirt plus a $58 fee. Which equation represents the number of shirts when both companies charge the same amount? 

• y = 9.65 + x
  y = 8.40 + x

• y = 9.65x + 43
  y = 8.40x + 58

• y =9.65x
  y = 8.40x

• y = 9.65x - 43
  y = 8.40x - 58

There are 50 donkeys and chickens on a farm.  There are a total of 174 legs.  Which system below can be used to figure out how many of each animal the farm has?

• d + c = 174
  4d + 2c = 50

• d + c = 50
  4d + 2c = 174

• d + c = 50
  2d + 4c = 174

• d + c = 174
  2d + 4c = 50

The cost of 5 squash and 2 zucchini is $1.32. Three squash and 1 zucchini cost $0.75. Write a system of equations.

• 5q + 2z = 1.32

  1z = 0.75

• 5q + 2z = 1.32

  3q + 1z = 0.75

• q + z = 1.32

  q + z = 0.75

• 5q + 2z = 0.75

  3q + 1z = 1.32

Last season two running backs on the Steelers football team rushed a combined total of 1550 yards.  One rushed 4 times as many yards as the other. Which system of equations could be used to determine the number of yards each running back rushed? 

• x + y = 1550
  y  = 4x

• x + y = 1550
  y = x + 4

• y - x = 1550
  y = 4x

• y = 1550 + x
  y = x + 4

Josh is thinking of two numbers.  Their sum is -10 and their difference is -2.  Which system of equations represents the situation?

• x - y = -10
  x + y = -2

• x = -2 
  y = 5

• x + y = -2
  x - y = -10

• x + y = -10
  x - y = -2

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

Dennis mowed his next door neighbor’s lawn for a handful of dimes and nickels, 80 coins in all.  Upon completing the job he counted out the coins and it came to $6.60.  Which system of equations could be used to find the exact number of dimes and nickels? 

• d + n = 6.60
  .10d + .05n = 80

• d + n = 80
  d + n = 6.60

• d + n = 80
  .10d + .05n = 6.60

• d + n = 80
  .05d + .10n = 6.60

Two high schools planned senior trips. High school A rented 1 van and 6 buses. They took 372 students. High school B rented 4 vans and 12 buses. They took 780 students. How many students does a van and bus hold?

• A van holds 18 students and a bus holds 59 students.

• A van holds 59 students and a bus holds 18 students.

• A van holds 24 students and a bus hold 54 students.

• A van holds 54 students and a bus holds 24 students.

Manassas Park is selling tickets for their fall musical. On the first day of sales, we sold 3 adult tickets and 9 student tickets. They made $75. On the second day of sales, we sold 8 adult tickets and 5 student tickets and made $67. How much does an adult and a student ticket cost?

• An adult ticket costs $4 and a student ticket costs $7.

• An adult ticket costs $7 and a student ticket costs $4.

• An adult ticket costs $6 and a student ticket costs $3.

• An adult ticket costs $3 and a student ticket costs $6.