Question

How many gallons of gas will Justin need to drive 120 miles? Use a table or proportionas

Answer 1

As you can see, both variables are directly proportional.

Thus, the given line should have the form:

`y=kx`

Where k is the proportionality constant.

To find the number of gallons of gas needed to drive 120 miles, we should find k first.

Notice that we need 1 gallon of gas to drive 25 miles and 2 gallons of gas to drive 50 miles. The rate of change (k) between these variables is:

`(50-25)/(2-1)=25\frac{gallons}{\text{mile}}`

This means that it takes 25 gallons to drive each mile.

Now, we could replace:

`\begin{gathered} 120=25x \\ x=(120)/(25)=4.8\text{gallons} \end{gathered}`

Therefore, Justin needs 4.8 gallons to drive 120 miles.