Digital PSAT Math Practice Question 254: Answer and Explanation

Question: 254

A refrigerant manufacturer recorded the pressure associated with certain temperatures in a refrigerator using its new refrigerant, ABC. What would best approximate the equation of the best-fit line portrayed by the data in this graph, using P for pressure and T for temperature (using the same units as portrayed in the graph)?

• A. P = 0.5T + 6.5
• B. P = T + 6.5
• C. P = 0.5T - 3
• D. P = 7T + 5

Correct Answer: A

Explanation:

(A) The y-intercept of the function is somewhere between positive 6 and 8, so you can eliminate choices (C) and (D). Next, find the approximate slope. You can use any two points on the line of best fit, such as the endpoints:

, so the answer is (A). The line has a slope of 0.5 and a y-intercept of 6.5.