To find out how many ounces of blueberries Trevor picked each mile, we need to divide the total amount of blueberries he collected by the total distance he walked.
Trevor collected a total of 50 ounces of blueberries over a 3-mile walking path:
\[ \text{Ounces per mile} = \frac{\text{Total ounces}}{\text{Total miles}} = \frac{50 \text{ ounces}}{3 \text{ miles}} \]
Now, performing the division:
\[ \frac{50}{3} = 16 \frac{2}{3} \text{ ounces} \]
So, Trevor picked
\[ \frac{50}{3} \text{ ounces} \]
or as a mixed number:
\[ 16 \frac{2}{3} \text{ ounces per mile.} \]
Thus, the answer is:
\[ \frac{50}{3} \text{ ounces per mile.} \]