Writing an equation
Let's say x is the number of ounces. Since the cost for each ounce is $0.85 then we can find the cost for the total amount of ounces by multiplying it by the cost of each one:
$0.85 · x
This is not the total cost, since the total cost has an additional of $5.50. Then the total cost is given by
c = $5.50 + $0.85x
Answer: C: c = 0.85x + 5.50
