SAT Math Multiple Choice Question 511: Answer and Explanation
1. The USDA recommends that adult females consume 75 mg of ascorbic acid, also known as vitamin C, each day. Because smoking inhibits vitamin absorption, smokers are encouraged to consume an additional 35 mg daily. If one grapefruit contains 40 mg of vitamin C and one serving of spinach contains 10 mg, which of the following inequalities represents the possible intake of grapefruit g and spinach s that a smoking female could consume to meet or surpass the USDA's recommended amount of vitamin C?
- A. 40g + 10s ≥ 75
- B. 40g + 10s ≥ 110
- C. 40g + 10s > 110
Correct Answer: B
Category: Heart of Algebra / Inequalities
Strategic Advice: When trying to match an inequality to a real-world scenario, you need to examine the numbers, the variables, and the inequality symbol.
Getting to the Answer: The question asks how much is needed to meet or surpass the recommended amount, which is another way of saying greater than or equal to, so you can eliminate C. Adult females should consume 75 mg of vitamin C, and smokers should consume an additional 35 mg, so the total amount that a smoking female should consume is 75 + 35 = 110 mg. This means the right-hand side of the equation should be ≥ 110, and you can eliminate A. To choose between (B) and D, think in concrete terms. Multiplying (not dividing) the number of mg in each grapefruit or serving of spinach yields the total amount of vitamin C in each, so (B) is correct.