Michael likes to eat chips and ice cream. Michael purchased 10 units (bags) of chips at $2 per unit, and his marginal utility of the last unit of chips purchased was 12 utils. Michael purchased 7 units (containers) of ice cream at $4 per unit, and his marginal utility of the last unit of ice cream purchased was 20 utils. If Michael is spending all of his money on these two snacks, should he purchase more chips and less ice cream, purchase more ice cream and less chips, or stay at the same purchase level (10 units of chips and 7 units of ice cream) to maximize his utility? Why?