Equation Models

Kelly's younger brother, Grayson, had his birthday party at the Dinosaur Discovery Center. Kelly's parents paid a total of $208 for all 13 kids that attended. During the party, Grayson and his friends got to mine for fossils and see real dinosaur tracks!

Let c represent the cost for each kid. Which equation models the problem?

• 13c = 208

  c = 16

• c/13 = 208

  c = 2,704

For his science fair project, Aaron studied how bees make honey. Now, he's drawing a diagram of a honeycomb cell on a poster board. He draws a regular hexagon with a perimeter of 102 centimeters.

Let l represent the length of each side of the hexagon. Which equation models the problem?

• l/6 = 102

  l = 612

• 6l = 102

  l = 17

Users of the video app Webbed Flicks are required to watch 15-second ads before they can watch their video. Grace watched ads for 60 seconds before her video started.

Let x represent how many ads Grace had to watch. Which equation models the problem?

• 15x = 60

  x = 4

• x/15 = 60

  x = 900

What strategy should I be using to solve equations like:

3f = 6

f = ?

• Multiply 6 and 3

• Divide 6 and 3

• Multiply 3 and f

• Divide 3 and f

The perimeter of a square is 176 inches.

Let s represent the length of each side of the square. Which equation models the problem?

• 4s = 176

  s = 44

• s/4 = 176

  s = 704

Carrie bought a bag of Classy Canine dog food for her dog Squiggle. The bag had enough food to last 15 days. Squiggle gets 3 cups of dog food each day.

Let d represent the amount of dog food in the bag at the start. Which equation models the problem?

• 3d = 15

  d =

• d/15 = 3

  d = 45

Mike's Media Market buys and sells used video games. Lily decided to sell her set of 8 Throttle Escape video games since she had beaten each game. She got $103.60 for the entire set.

Let v represent how much money Lily got for each video game. Which equation models the problem?

• 8v = 103.60

  v = 12.95

• v/8 = 103.60

  v = 828.8

To find the variable in a math equation, I should use the inverse operation of what is being presented to me.

• True

• False

The cookie-stacking competition is a tradition at Westhaven's annual summer festival, and Bert is helping to set it up this year. The first contestant who creates a single stack using all of their cookies wins a prize! After Bert split all the cookies he had evenly among 4 contestants, each contestant got 24 cookies.

Let c represent how many cookies Bert had to start. Which equation models the problem?

• 4c = 24

  c = 6

• c/4 = 24

  c = 96

Mr. Ramsey planted a rose garden in his backyard. He divided the garden into 12 equal sections so he could plant a different kind of rose bush in each. Each section had an area of 4 square feet.

Let g represent the area of the garden. Which equation models the problem?

• g/12 = 4

  g = 48

• 4g = 12

  g = 3