Good X and good Y are substitutes. If the price of good Y increases, then the
demand for good X will increase.
To understand why this is the case, we need to consider the concept of substitutes in economics. Substitute goods are goods that can be used in place of each other to fulfill similar needs or desires. When the price of one substitute increases, consumers tend to switch to the other substitute.
In this scenario, good X and good Y are substitutes. This means that they serve a similar purpose, and if the price of good Y increases, consumers are more likely to choose good X instead. This is because as the price of Y rises, it becomes relatively more expensive compared to X. Therefore, consumers will demand more of good X as an alternative to the now pricier good Y.
To summarize, if the price of good Y increases, the demand for good X will increase because consumers will switch to good X as a substitute for the more expensive good Y.