The price of petrol fell during the past year.
a. Explain why the law of demand applies to petrol just as it does to all other goods and services.
b. Explain how the substitution effect influences petrol purchases and provide some examples of substitutions that people might make when the price of petrol falls and other things remain the same.
c. Explain how the income effect influences petrol purchases and provide some examples of the income effects that might occur when the price of petrol falls and other things remain the same