To determine the inequality that represents the possible values of \( m \), the number of miles Mr. Estrada can travel with the remaining gasoline, we start with the total distance he can travel on a full tank, which is 510 miles. After traveling 194 miles, we can find the remaining distance he can travel by subtracting the distance he has already traveled from the total distance:
\[ m \leq 510 - 194 \]
Calculating the right side:
\[ 510 - 194 = 316 \]
This means the inequality representing the remaining miles \( m \) is:
\[ m \leq 316 \]
So, the correct answer is:
J: \( m <_ 316 \)