Explanation:
1. If butter complements margarine for instance, and there occurs a sudden increase in the price of butter leading to lower demand, this would affect the demand for margarine negatively leading to a fall in the demand for margarine.
2. If this goods are substitutes the demand for butter will increase when the price of margarine rises.
This is because it is only natural for people to switch to the next best alternative (substitute) that fills the same purpose or needs.
3. Remember Ice cream and ice cream cones complementary goods; meaning the demand for one increases the demand for the other and vice versa.
4. If the price of ice cream increases, demand would also decrease for ice cream as consumers are usually sensitive to price.
This decrease in the demand for ice cream would also affect ice cream cones since they complement each other, leading to a decrease in the demand for ice cream cones.
Nothing really, you just might have a better idea of your budget if you do.
