Question

The graph below shows the gasoline consumption by Ms. LaTour's car when she drives on the highway.

Using the information provided by the graph, how many gallons of gasoline should it take for Ms. LaTour to drive her car 325 miles on the highway?

Answer 1

To drive 325 miles she needs 13 gallons of gasoline.

How many gallons of gasoline should it take for Ms. LaTour to drive her car 325 miles on the highway?

We can see that this is modeled by a linear equation. Remeber that a linear equation is written as:

y = a*x + b

Where a is the slope and b is the y-intercept.

Looking at the graph we can see that the y-intercept is 0, so:

y = a*x

We can see that the line passes through (6, 150), then:

150 = a*6

150/6 = a

25 = a

y = 25*x

Then for 325 miles, we need to solve:

325 = 25*x

325/25 = x

13 = x

So you need 13 gallons.