Digital PSAT Math Practice Question 306: Answer and Explanation

Question: 306

The Asian carp has experienced a rapid growth by displacing other fish in the Mississippi River. A researcher gathered three yearly samples from a 500-meter length of the Upper Mississippi River to determine the population trend of the fish over a decade.

What is the approximate slope of the best-fit line of the data in the graph, expressed as change in carp per year?

• A. 3.3
• B. 4.8
• C. 5.7
• D. 7.6

Correct Answer: A

Explanation:

(A) Some approximate points that would be on the best-fit line are (1990, 0) and (1996, 18). Calculate the approximate slope: 18 - 0/1996 - 1990 = 3, which comes closest to choice (A). You can also visualize this by drawing the approximate best-fit line on the graph: