PSAT Math Multiple-Choice Question 36: Answer and Explanation

Question: 36

Jodi has x dollars in her bank account. She withdraws of the money in her account to pay her rent and another of the money in her account to make her car payment. Jodi then deposits her paycheck of y dollars into her account. A week later, she withdraws of the money in her account to spend on a new set of knives. In terms of x, how many dollars are left in Jodi's account?

• A.
• B.
• C.
• D.

Correct Answer: D

Explanation:

D

The question asks for a value in terms of a variable. There are variables in the answer choices, and the question includes the phrase in terms of, so plug in. The problem involves taking of the amount in the account, so choose a number for x that is divisible by 6. Make x = 18. Now work the question in Bite-Sized Pieces. of the $18 in the account is 18 × = 3. That means Jodi withdraws $3 and has $18 - $3 = $15 remaining. Then she withdraws another $3 and has $15 - $3 = $12 remaining. Next, Jodi deposits y dollars into her account. Make y = $8. Jodi has $12 + $8 = $20. Last, Jodi withdraws half the money in her account, so she withdraws $10 and has $20 - $10 = $10 left in her account. This is the target; circle it. Plug x = 18 and y = 8 into the answer choices to see which one matches the target value. Choice (A) becomes . Continue simplifying the expression to get . This does not match the target, so eliminate (A). Choice (B) becomes . Continue simplifying to get . Eliminate (B). Choice (C) becomes . Continue simplifying to get . Eliminate (C). Choice (D) becomes . Continue simplifying to get . This matches the target. The correct answer is (D).