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Helppop!!A car and van are driving on a highway. The table shows the amount y (in gallons) of gas in the cars gas tank after driving x miles. The amount of gas in the van’s gas tank after driving x miles is represented by the equation y=- 1/5x + 31. Which vehicle uses less gasoline per mile? How many miles must the vehicles travel for the amount of gas in each tank to be the same?

HelppopA Car And Van Are Driving On A Highway The Table Shows The Amount Y In Gallons Of Gas In The Cars Gas Tank After Driving X Miles The Amount Of Gas In The class=

Sagot :

Answer:

The car uses less gas

They use the same amount of gas after [tex]\frac{640}{7}[/tex] miles

Step-by-step explanation:

Given

The table represents the car mileage

[tex]y = -\frac{1}{5}x + 31[/tex] --- The van

First, calculate the car's slope (m)

[tex]m = \frac{y_2 - y_1}{x_2 - x_1}[/tex]

From the table, we have:

[tex](x_1,y_1) = (60,13.5);\ \ (x_2,y_2) = (180,10.5)[/tex]

So, we have:

[tex]m = \frac{10.5 - 13.5}{180 - 60}[/tex]

[tex]m = \frac{-3}{120}[/tex]

[tex]m = -\frac{1}{40}[/tex]

Calculate the equation using:

[tex]y = -\frac{1}{40}(x - 60)+13.5[/tex]

[tex]y = -\frac{1}{40}x + 1.5+13.5[/tex]

[tex]y = -\frac{1}{40}x + 15[/tex]

[tex]m = -\frac{1}{40}[/tex] implies that for every mile traveled, the car uses 1/40 gallon of gas

Also:

[tex]y = -\frac{1}{5}x + 31[/tex] --- The van

By comparison to: [tex]y = mx + b[/tex]

[tex]m = -\frac{1}{5}[/tex]

This implies that for every mile traveled, the van uses 1/5 gallon of gas.

By comparison:

[tex]1/40 < 1/5[/tex]

This means that the car uses less gas

Solving (b): Distance traveled for them to use the same amount of gas.

We have:

[tex]y = -\frac{1}{5}x + 31[/tex] --- The van

[tex]y = -\frac{1}{40}x + 15[/tex] --- The car

Equate both

[tex]-\frac{1}{5}x + 31 =-\frac{1}{40}x + 15[/tex]

Collect like terms

[tex]\frac{1}{40}x -\frac{1}{5}x =-31 + 15[/tex]

[tex]\frac{1}{40}x -\frac{1}{5}x =-16[/tex]

Take LCM

[tex]\frac{x - 8x}{40} = -16[/tex]

[tex]\frac{- 7x}{40} = -16[/tex]

Solve for -7x

[tex]-7x = -640[/tex]

Solve for x

[tex]x = \frac{640}{7}[/tex]