SAT Math Multiple Choice Question 392: Answer and Explanation
Which of the following lists correctly orders the lines in the figure above according to their slopes, from least to greatest?
- A. R, T, S, U
- B. S, U, R, T
- C. S, R, U, T
- D. U, S, R, T
Correct Answer: B
Category: Heart of Algebra / Linear Equations
Strategic Advice: A horizontal line has a slope of 0. Lines that slant downward from left to right have a negative slope, and lines that slant upward from left to right have a positive slope.
Getting to the Answer: Only one line has a negative slope, S, so it should come first in the list. This means you can eliminate A and D. Next comes the horizontal line with a slope of 0, which is line U. You can now eliminate C, which means (B) must be correct. To confirm (which isn't absolutely necessary), there are two lines with positive slopes: R and T. Line T has a steeper slant than line R, which means line T has a greater slope; therefore, the correct ordering is S, U, R, T.