Digital PSAT Math Practice Question 328: Answer and Explanation

Question: 328

If n represents m percent of x, how could the value of n be calculated?

Correct Answer: A

Explanation:

(A) The formula for calculating a percentage is Part/Whole × 100 = Percentage.

So m represents the overall percentage, n represents the part, and x represents the whole. Plugging these values into the original equation gives:

\begin{matrix} Part / Whole \times 100 = Percentage \to \\ n / x \times 100 = m \to \\ n = m x / 100 \end{matrix}

Alternatively, you can rephrase the question using concrete numbers:

"If 10 represents 50 percent of 20, how can we calculate the value of 100?" The only solution that gives the correct answer is choice (A):

\begin{matrix} Part / Whole \times 100 = Percentage \to \\ 10 / 20 \times 100 = 50 \to \\ 10 = (50 \times 20) / 100 \to \end{matrix}

This equation is in the same format as the equation shown in choice (A):

n = m x / 100