Marge Buys 5 CDs and 7 DVDs

Multiple Choice

Marge buys 5 CDs and 7 DVDs.The marginal utility of the 5th CD and the marginal utility of the 7th DVD are both equal to 30 utils.Can we say that this is the optimal combination of CDs and DVDs for Marge?

A) No. We need to know her preferences for CDs and DVDs.
B) Yes.
C) No. For this to be the optimal combination, the total utility from her purchase of CDs needs to equal the total utility from her purchase of DVDs.
D) No. If this was the optimal combination, the marginal utility per dollar of the 5th CD and the 7th DVD would be equal.