Answer:
2 people
Step-by-step explanation:
Total number of people (n) = 50
Borderlands II (B) = 20
Fortnite (F) = 33
Minecraft (M) = 19
Borderlands and Fortnite (B&F) = 15
Borderlands and Minecraft (B&M)= 10
All games (B&M&F) = 5
The number of people that claimed more than one game as their favorite (X) is given by:
Those people can be divided in B&F only, B&M only, M&F only and B&M&F:
7 people claimed that Minecraft and Fortnite were their favorites however, 5 of those people claimed all of the games as their favorite. Therefore, only 2 people declared Minecraft and Fortnite (exclusively) as their favorites.