SAT Math Multiple Choice Question 65: Answer and Explanation
5. The number of bonus points, B(p), that a credit card holder receives is given by the function B(p) = 4p + 7, where p represents the number of purchases made. If the number of purchases is increased by 3, by how much does the number of bonus points increase?
- A. 3
- B. 4
- C. 12
- D. 19
Correct Answer: C
C Whenever there are variables in the question and the answer choices, think Plugging In. If 2 purchases were made, then p = 2, and the number of bonus points can be calculated as 4(2) + 7 = 8 + 7 = 15. If the number of purchases were then increased by 3, the new p equals 5 and the number of bonus points can be calculated as 4(5) + 7 = 27. The bonus points increased by 27 - 15 = 12. Therefore, the correct answer is (C).