Let's denote the price of an adult ticket as \( x \).
The total cost for the group of 4 students and 3 adults can be expressed as:
\[ 4 \times 7 + 3 \times x = 64 \]
Calculating the total cost for the students:
\[ 4 \times 7 = 28 \]
So the equation becomes:
\[ 28 + 3x = 64 \]
Now, subtract 28 from both sides:
\[ 3x = 64 - 28 \] \[ 3x = 36 \]
Now, divide both sides by 3 to find \( x \):
\[ x = \frac{36}{3} = 12 \]
Thus, each adult ticket costs $12.