AP Microeconomics 1.6: Consumer Choice
Learn how rational consumers maximize utility under income and price constraints by comparing marginal utility per dollar across available goods.
- Syllabus
- Effective Fall 2025
- Course
- AP Microeconomics
Learn how rational consumers maximize utility under income and price constraints by comparing marginal utility per dollar across available goods.
The table provided shows the marginal utility for Lucy when she consumes Good X and Good Y.

If Good X and Good Y are free, how many units of each good will maximize Lucy's total
utility?
| A Point 1 | State that Lucy will maximize her total utility by consuming 5 units of Good X and 4 units of Good Y. | 1 point |
|---|
Calculate Lucy's total utility if she consumes 2 units of Good X and 2 units of Good Y. Show
your work.
| B | |
|---|---|
| Point 2 | Calculate Lucy's total utility of consuming 2 units of Good X and 2 units of Good Y as 88 utils and show your work. |
| Total Utility from consuming 2 units of Good X = 20 utils + 16 utils = 36 utils | |
| Total Utility from consuming 2 units of Good Y = 28 utils + 24 utils = 52 utils | |
| Total Utility from consuming 2 units of Good X and 2 units of Good Y = 36 utils + 52 utils = 88 utils | 1 point |
Suppose instead that the price of each unit of Good X is $2 and the price of each unit of Good
Y is $4. Lucy has a budget of $20 to spend on the two goods.
If Lucy purchases 2 units of Good X, what is the maximum quantity of Good Y Lucy can
purchase?
| Point 3 | State that Lucy can purchase a maximum of 4 units of Good Y. | 1 point |
|---|
What is Lucy's optimal combination of Good X and Good Y? Explain your answer using
marginal analysis and numbers.
(ii) \\ Point 4 \end{tabular} & State that Lucy's optimal consumption is 4 units of Good X and 3 units of Good Y and explain that at this combination, the marginal utility per dollar spent on the last unit of Good X is 4 utils/ $(=8 utils /$2), and the marginal utility per dollar spent on the last unit of Good Y is 4 utils/ $(=16 utils /$4) when Lucy spends her entire budget of $20 ( =$2×4 units of Good X + $4 × 3 units of Good Y). & 1 point \\