SAT Math Multiple Choice Question 81: Answer and Explanation
6. Once a certain plant begins to grow, its height increases at a linear rate. After six weeks, the plant is 54 centimeters tall. Which of the following functions best models the relationship between h(w), the height, in centimeters, of the plant, and w, the number of weeks that the plant has been growing?
- A. h(w) = 6w
- B. h(w) = 9w
- C. h(w) = 54w
- D. h(w) = 54 + w
Correct Answer: B
BThe question states that after 6 weeks the plant is 54 centimeters tall. Therefore, when w = 6, h(w) = 54. Plug in 6 for w in the answers to see in which answer h(w) equals the target number of 54. In (A) h(w) = 6(6) = 36. Eliminate (A). In (B), h(w) = 9(6) = 54. The correct answer is (B).