Word Problems and Lines Examples

For the following situation, 

1. Decide what quantities the independent variable (x) and dependent variable (y) should represent.
2. Draw a graph of the situation.
3. Write a linear equation describing the situation.

Bobby has a lemonade stand and charges 25 cents for each glass of lemonade. Don't tell anyone, but he cuts the lemonade with  water to increase his profit margin. Did someone teach this kid right or what?

1. x is the number of glasses of lemonade Bobby sells; y is the amount Bobby makes.
2. 
3. y = 0.25x for x ≥ 0

For the following situation,

1. Decide what quantities the independent variable (x) and dependent variable (y) should represent.
2. Draw a graph of the situation.
3. Write a linear equation describing the situation.

Joe lives 20 miles to the east of a very nice park. He left his home at 1 p.m. and drove east for 3 hours. When he stopped, he was 206 miles away from the park. The birds had finally stopped following him.

1. x is how long Joe has been driving; y is how far away he is from the park.
2. 
3. y = 62x + 20 for x ≥ 0 

For the following situation, 

1. Decide what quantities the independent variable (x) and dependent variable (y) should represent.
2. Draw a graph of the situation.
3. Write a linear equation describing the situation.

Aunt Marjie doesn't like going outside in the cold. Seriously...she's a big baby about it. If it's -10° F she'll only stay outside for 2 minutes, but if it's 70° F she'll stay out for 2 hours. Even at 70° though, she's still complaining.

1. The amount of time Aunt Marjie will stay out depends on the temperature, so x is the temperature in degrees Fahrenheit, and y is the number of minutes Aunt Marjie will stay out. (We could instead let y be the number of hours Aunt Marjie will stay out, but it's hard to graph th of an hour.)
2. 
3. or any equivalent equation.