PSAT Math Multiple-Choice Question 822: Answer and Explanation

Question: 822

If a line were graphed using the quantity sold in Store D as the x-value and the price from Store D as the y-value, what would be closest to the y-intercept of the line?

• A. 12.2
• B. 14.4
• C. 17.4
• D. 20.8

Correct Answer: C

Explanation:

(C) Calculate the slope of the line:

Then create an equation for the line in slope-intercept form (y = mx + b) and solve for the y-intercept:

y = -0.015625x + b

Substitute a set of values from Store D to solve for b:

14 = (-0.015625 × 220) + b → b ≈ 17.4