Math question please help!?

Question

The following information shows a relationship between the speed of a certain car over a 100-mi test trip and the gas mileage obtained:

Speed 40 45 50 55 60

Gas mileage 35 33 28 25 22

predict the gas mileage associated with a speed of 65 mi/h.

Answer 1

Here is the way I would figure this out. Add up the decrements in gas mileage over the four increments in speed. When you do that, you get:

mpg (t) = -2 + (-5) + (-3) + (-3) = -13 mpg

To find the average decrement in gas mileage, divide the figure above by the number of 5 mph increments in speed. There are 4.

mpg (t)/4 = -13/4 = -3.25.

So, based on the average decrease in gas mileage for every 5 mph increase in speed, we can predict that if the car speeds up to 65 mph, the mileage will decrease by about 3.25 mpg under its mpg rating at 60 mph.

mpg at 65 mph = 22 - 3.25 = 18.75 mpg.

Answer 2

18.4
Your data does not reside on an absolutly straight line, but very close to it.
The way i determined the forcast is by plotting it on an excel worksheet and graph
one of the options on graphs is to create a trendline and display the equation that i did the extrapulated result was 18.4

Answer 3

I'd say about 18.4.

I plotted them, then found the line of best fit (y = -0.68x + 62.6), and pluged in the value '65' for x, and it came out with 18.4.