I would solve this by calculating the percentage of dislikes that makes up to this amount of likes:
First one, "The True Science of Parallel Universes" would be:
5/300)*100 = 1.66
Second one, "did the Past Really Happen?" would be:
7/400)*100 = 1.75
The first one has less dislikes compared to likes. So "The True Science of Parallel Universes" is the video that is better liked