How does Marginal Rate of Substitution change along a budget line?

Question

How do you properly figure out the MRS along a budget line, I do not know how to correctly figure it out, since I end up with the same MRS all along the line.

Answer 1

Since the budget line is linear, the slope IS a constant, and the MRS IS a constant. Utility is maximized where the utility curve is tangent to the budget line, that is where the slope of the Utility curve is equal to that constant.

Answer 2

Marginal rate of Substitution is essentially the slope of the line... if the *line* is linear, you will have the same MRS. If the line is actually a curve, then the MRS can change along the curve depending on the different quantity.