why are we substituting x by 3.2 and not 3200 in this problem? The answer is a. Substitute x = 3.2 into the regression equation and simplify

The weights of 140 small to midsize cars and their lengths were recorded and a linear regression was performed on the data. The weights of the cars ranged from 2500 pounds to 3600 pounds. The least squares regression line for the data has the equation y=22.60x+109.01 where x is the weight of the car in thousands of pounds and y is the length of the car in inches. What is the predicted length (to the nearest inch) of a car that weights 3200 pounds?

a) 181 in b) 185 in c) 72,429 in d) 144,717 in