the optimal quantity of pizza slices for John to buy is 1.
According to economics, the optimal quantity of a good that should be consumed is the quantity at which the marginal utility equals the marginal cost.
Marginal utility is the change in utility when consumption is increased by one unit. Marginal cost is the change in total cost when consumption is increased by one unit. The unit at which marginal cost is equal to marginal utility is 1.
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