ii. Mr. Robinson makes $200 a week and spends his entire income on running shoes and basketball shorts. a. Write down the algebraic expression for his budget constraint if running shoes and basketball shorts cost $20 each. How many of each good will he buy? [3 marks]. b. Write down the algebraic expression for Mr. Robison's budget constraint if the price of basketball shorts rises to $30 each. How many of each good will he buy? [3 marks] c. Illustrate the results in parts (a) and (c) and provide a decomposition of the income and substitution effect. [6 marks]