The miles he drove North on Avenue B is 24 miles.
According to the Pythagoras theorem, the square of the hypotenuse is the sum of the square of the opposite sides.
The Pythagoras theorem: a² + b² = c²
Where:
25² - 7²
625 - 49 = 576
√576 = 24 miles
Please find attached the required diagram. To learn more about Pythagoras theorem, please check: https://brainly.com/question/14580675