Since he has two hours to get ready = 120 minutes
Assuming it takes 20 minutes for Pablo to get ready, and each episode is 25 minutes long, we can create the following expression:
Let x be the number of episodes he can watch
20+25x=120
25x=120-20
25x=100
x=100/25
x=4
Pablo can watch 4 episodes before he has to begin getting ready.