PSAT Math Multiple-Choice Question 681: Answer and Explanation

Question: 681

A square piece of paper is folded in half n times. If L is the length of an edge, what is the area of the piece of paper after it is folded in half n times?

• A.
• B.
• C.
• D.

Correct Answer: B

Explanation:

(B)

From the drawings, we can see that if the paper is folded in half once, the area is:

After the second fold:

After the third fold:

We can see that each time, the numerator stays the same while the denominator is multiplied by 2. Therefore, the numerator will always be L² while the denominator will be 2ⁿ. Therefore, area can be represented by:

Choice (B) is the correct answer.

Alternatively, you could have plugged the values for the areas for each fold into the answer choices to see that only choice (B) works.