Activities

1. Write an equation to show a rate increase of $10 per month using m for month and t for the total increase.

2. Jose and a few of his friends buy concert tickets that cost $55.00 each.  Write an equation to represent the relationship between the number of tickets n and the total cost x.

3. Bianca works at the mall and makes $12.50 per hour, but has to pay her mom $20 each week for money that she borrowed.  Write an equation to represent the relationship between the amount of money she makes per hour, h, and the total money earned, t, for one week.

4. When you take a cab you have to pay $5.75 to use the cab and then you pay $0.25 for every mile that they drive you.  Write an equation to represent the total cost, t, for m miles traveled.

5. A baseball league is printing shirts for all the kids that signed up to play this year.  It costs the league $7 per shirt to make them for the kids. Write an equation to represent the situation; be sure to identify what your variables represent.  Identify the independent and dependent variables and explain why.

6. Write a situation that would match the equation x = 5y.  Tell which variable is independent and which variable is dependent in the problem that you wrote.

Answer Key/Rubric

1. t = 10m

2. x = 55n

3.  t = 12.50h – 20

4. t = 5.75 + 0.25m

5. Students can use various letters for the variables, but must state what they represent:

Let t = total cost

Let s = number of shirts/kids

t = 7s

The independent variable is 7s.

Reasons might include, but are not limited to:

• The price of each shirt does not depend on how many shirts are ordered. 
• The price will stay $7 per shirt

The dependent variable is t. 

Reasons might include, but are not limited to:

• The total cost will depend on how many shirts are ordered
• If the price per shirt changed so would the total cost
• If the amount of shirts changes so would the total cost

6. Answers might include, but are not limited to:

• Example:  Each week I donate $5 to a different charity.
• x is the dependent variable in the equation; in the above example it would be the total donated
• The x value depends on the value of the y
• y is the independent variable; in the above example it would be the number of weeks
• Whatever example is given in the students’ situation the 5 will stay consistent.  In the example above the $5 donation does not depend on how many weeks the donation is being made.