. Model Problem
Coffee vs. Tea
A café by Lindsay's house sells coffee and tea. They are trying to make the most amount of money
possible. In other words they are trying to maximize profit. They asked me to look at their sales
receipts and figure out what they should do. But they had a few limitations on what could be done.
Constraint #1: The Baristas (the people who makes the coffee) can only reasonably serve 90 cups
per shift. It can be 90 cups of coffee, 90 cups of tea or a mixture of the two.
Constraint #2: Coffee costs $3 per cup and Tea costs $2. In order to stay on track to pay their
bills, the owners would like to sell at least $120 worth of beverages every shift.
Constraint #3: They have a limited supply of coffee and tea that gets delivered every day. If they
don't want to sell out (And annoy customers) they can sell no more than 70 cups of tea per shift.
Constraint #4: Similar to the last constraint, they can only sell 60 cups of coffee per shift before
they sell out.
Question: How much tea and how much coffee should they sell every shift in order to maximize
profits? They make $1.10 on each cup of coffee and $.90 on each cup of tea.