The table shows the total utility that Shanka derives from sweatshirts and Birkenstocks. The price of a sweatshirt is $50, and the price of a pair of Birkenstocks is $100. Shanka's income is $300. Quantity of sweatshirts Utility from Sweatshirts Quantity of Birkenstocks (Number of Pairs) Utility from Birkenstocks 0 0 0 0 1 500 1 800 2 600 2 1000 3 625 3 1100 The marginal utility per dollar of the first sweatshirt is