Answer: He watched 9 episodes over winter break.
Explanation:
Given: Total episodes watched = 45
After school started , he watched 9 episodes per week.
So in 4 weeks. he watched = 9 x 4 = 36 episodes.
Number of episodes he watched over winter break = 45-36
i.e. Number of episodes he watched over winter break = 9
Hence, he watched 9 episodes over winter break.