I think for this item, the rate at which the gasoline was consumed is to be calculated. To determine the distance that Stanley's car had traveled, we subtract 840 miles from 1,200 miles. That will give us an answer of 360 miles. Dividing this by 12 gallons will give us an answer of 30 miles/gal.
The table is linear because the change because it had a constant slope when we solve for change in y / change in x for each of the data points given. That slope is -0.5 and it’s constant.
