Final answer:
If one good has a negative income elasticity, it is an inferior good, and the other good has a positive income elasticity, making it a normal good.
Step-by-step explanation:
If one of the goods you buy has a negative income elasticity, it means that the good is inferior. An inferior good is a type of product that people buy less of as their income increases. Therefore, if the income elasticity of demand for one good is negative, the income elasticity of demand for the other good must be positive, indicating that it is a normal good