I went to Sam's club today to buy engine oil and they had two options. One liter bottles and four liter bottles. I only care about the total quantity of engine oil I buy. Let X stand for the quantity of one liter bottles and Y for the quantity of four liter bottles. Suppose that the price of one liter bottles of oil is $10 and the price of four liter bottles is $30. I have $60 to spend on engine oil. Suppose that Sam's club announces that it has a special, 40% off on one liter bottles of motor oil. How many one liter bottles and how many four liter bottles will I buy now? For simplicity assume that I can buy parts of a bottle