Digital PSAT Math Practice Question 252: Answer and Explanation

Question: 252

Caitlin opens a checking account to set aside spending money for vacations. Each month she puts the same dollar amount, $50, in the account. Unfortunately, she does not expect to be able to take a vacation at any point in the foreseeable future. What would best describe the relationship between the number of months and the total amount of money in the account?

• A. A linear relationship, with the line of the relationship having a negative slope
• B. A linear relationship, with the line of the relationship having a positive slope
• C. An exponentially increasing relationship
• D. An inverse exponential relationship

Correct Answer: B

Explanation:

(B) Each month, she adds $50, so the function will have a constant slope of 50. Because the slope is constant, the function is linear. The slope is positive 50, so the answer is (B). You know that the slope will be positive because the two variables are directly proportional: as time goes on, the amount of money in the account increases.