Final answer:
If one good is classified as an inferior good, the income elasticity of the other good depends on whether it is a normal good or a luxury good.
Step-by-step explanation:
If one of the goods you buy has a negative income elasticity and is classified as an inferior good, it means that the quantity demanded for that good decreases as income increases. To determine the income elasticity of the other good, we need to look at whether it is a normal good or a luxury good. If the other good is a normal good, then its income elasticity would be positive, indicating that the quantity demanded for that good increases as income increases. However, if the other good is a luxury good, its income elasticity could be either positive or negative, depending on the preferences and spending habits of consumers.