Question

The function f(x)=30+0.25x/x yields the average cost in dollars per cup of lemonade made by Lincoln at his lemonade stand when he makes x cups of lemonade. Which statement best fits the situation modeled by the function?
Lincoln sells lemonade for 25 cents a cup.
Lincoln gave away 30 cups of lemonade for free.
Lincoln uses 25 cents worth of supplies per cup.
Lincoln uses 30 cents worth of supplies per cup.

Answer 1

Interpreting f(x) = (30 + 0.25x)/x = 30/x + 0.25, the 30/x is a fixed $30 spread over x cups (fixed cost per cup) and 0.25 is a constant cost per cup. So the best statement is:

Lincoln uses 25 cents worth of supplies per cup.