To find out how many ounces of popcorn your friend ate, we need to calculate \( \frac{1}{4} \) of \( 13 \frac{1}{3} \) ounces.
First, convert \( 13 \frac{1}{3} \) to an improper fraction:
\[ 13 \frac{1}{3} = \frac{40}{3} \text{ ounces} \]
Next, calculate \( \frac{1}{4} \) of \( \frac{40}{3} \):
\[ \frac{1}{4} \times \frac{40}{3} = \frac{40}{12} = \frac{10}{3} \text{ ounces} \]
Now, convert \( \frac{10}{3} \) back to a mixed number:
\[ \frac{10}{3} = 3 \frac{1}{3} \text{ ounces} \]
So, your friend ate 3 1/3 ounces. The answer is:
3 1/3 ounces.