PSAT Math Multiple-Choice Question 90: Answer and Explanation

Question: 90

At an organic farm, a 2.6 square kilometer plot of soybeans is being harvested. If the farm workers can harvest 23 hectares a day, which of the following functions can be used to estimate how many hectares, H(d), will remain to be harvested after d days?

(Note: 100 hectares = 1 square kilometer)

• A. H(d) = 2.6 - 0.23d
• B. H(d) = 2.6 - 23d
• C. H(d) = 260 - 23d
• D. H(d) = 2,300 - 260d

Correct Answer: C

Explanation:

C

The question asks for the function that gives the hectares remaining to be harvested after d days. Translate the information in Bite-Sized Pieces and eliminate after each piece. One piece of information says that the farm workers can harvest 23 hectares a day. Therefore, each day there are 23 fewer hectares remaining to be harvested, so the function must include -23d. Eliminate (A) and (D), which do not contain this term. Compare the remaining choices. Choices (B) and (C) differ by the first term. The question states that the farmers are harvesting a 2.6 square kilometer plot, but the question refers to the function in hectares. The note after the question indicates that there are 100 hectares in 1 square kilometer, so 2.6 square kilometers is equivalent to 2.6 × 100 = 260 hectares. Eliminate (B), which does not contain this number. The correct answer is (C).