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**magentarita** A store advertises that during its Labor Day sale $15 will be deducted from every purchase over $100. In addition, after the deduction is taken, the store offers an early-bird discount of 20% to any person who makes a purchase before 10 a.m. If Hakeem makes a purchase of *x* dollars,

*x* > 100, at 8 a.m., what, in terms of *x*, is the cost of Hakeem’s purchase?

(1) 0.20*x -* 15 (3) 0.85*x* - 20

(2) 0.20*x* -3 **(4) 0.80***x* - 12...This is the answer.

MY Work:

I understand the situation in the question. The correct answer is highlighted in red. I selected choice (1) given the fact that Hakeem purchased an item over $100 and that the store offers a discount of $15 and an additional discount of 20%.

It made sense to easily come up with 0.20x - 15. In fact, I also decided to let C = cost and then went on to develop the equation C = 0.20x - 15.

Why is choice (4) correct and my answer incorrect?