SAT Math Multiple Choice Question 783: Answer and Explanation
3. Darien needs to buy several white dress shirts for his new job. He finds one he likesfor $35 that is on sale for 40% off. He also likes a blue tie that costs $21. Whichof the following represents the total cost, not including tax, if Darien buys x of the white shirts that are on sale and two of the blue ties?
Correct Answer: C
Category: Heart of Algebra / Linear Equations
Strategic Advice: When matching an equation to a real-world scenario, take a quick look at the answer choices to see what variables are being used. Next, write an equation in words, and then use the Kaplan Strategy for Translating English into Math.
Getting to the Answer: Keep in mind that the shirts are on sale but the tie is not. The shirts are 40% off, which means that Darien pays only 100 - 40 = 60% of the price, or 0.6(35). If he buys x shirts, the cost is 0.6(35)x. He also buys two ties, which cost $21 each. This means the total cost is C = 0.6(35)x + 21(2). This is not one of the answer choices, so simplify to get C = 21x + 42, which is (C).