Total & Marginal Utility:
#) Total Utility: The aggregate level of satisfaction or fulfillment that a consumer receives through the consumption of a specific good or service. Each individual unit of a good or service has its own marginal utility, and the total utility is simply the sum of all the marginal utilities of the individual units.
+> Classical economic theory suggests that all consumers want to get the highest possible level of total utility for the money they spend.
#) Marginal utility: Marginal utility is an important economic concept because economists use it to determine how much of an item a consumer will buy.
+> Positive marginal utility is when the consumption of an additional item increases the total utility.