The coffee shop near the local college normally sells 10 ounces of roasted coffee beans for $10.00.But the shop sometimes puts the beans on sale.During some sales, it offers "33 percent more for free". Other weeks, it takes "33% off" the normal price.After reviewing the shop's sales data, the shop's manager that "33% more for free" sells a lot more coffee than the "33 percent off".Are the store's customers making a systematic error?Which is actually the better deal?