Finding the Optimal Choice
The optimal choice from a combination of goods is attained when all income is spent, and the consumer is on the highest attainable indifference curve.
In other words, the optimal choice is attained when the budget line is tangent to the indifference curve.
Changes to Price
Recall that the budget line can be moved when there is a change in price of a good. When the budget line is moved, the optimal choice will also be changed.
We will look at 4 different cases in which the budget line changes, and how it affects the optimal choice.
Case 1: A decrease in the price of good x.
In this case, you can attain an indifference curve with higher utility, thus gaining a better optimal choice.
Case 2: An increase in the price of good x.
In this case, you attain an indifference curve with lower utility, thus attaining a lower optimal choice.
Case 3: A decrease in the price of good y.
In this case, you can attain an indifference curve with higher utility, thus gaining a better optimal choice.
Case 4: An increase in the price of good y.
In this case, you attain an indifference curve with lower utility, thus attaining a lower optimal choice.
Changes to Income
Recall that the budget line can be shifted when there is a change in income. Let’s look at two cases where the budget line shifts, and how it affects the optimal choice.
Case 1: A decrease in income.
In this case, you attain an indifference curve with lower utility, thus attaining a lower optimal choice.
Case 2: An increase in income.
In this case, you can attain an indifference curve with higher utility, thus gaining a better optimal choice.