Answer:
I think there might be more to this question, but the answer I have is
3x + 50 > 80
Explanation:
If he has 50 points, needs higher than 80 points to advance to the intermediate level and receives 3 points for every puzzle he solves correctly, he must multiply the 3 by something to add to 50 to get a total amount higher than 80. Thus, 3x + 50 > 80 is the appropriate answer. Have a good day!