A total of 90 students are in the sports group.
30 students play football.
40 students play Volleyball.
25 students play basketball.
15 students play both football and volleyball.
10 students play both football and basketball.
8 students play both volleyball and basketball.
5 students play all the three games.
Now, we will subtract the number of students playing each game from the total number of students in the group to find the number of students who are not playing any of the games.
First, let's find the number of students who are playing at least one game.
30 (students playing football) + 40 (students playing volleyball) + 25 (students playing basketball) - 15 (students playing both football and volleyball) - 10 (students playing both football and basketball) - 8 (students playing both volleyball and basketball) + 5 (students playing all three games) = 63
So, 63 students are playing at least one game.
Therefore, 90 (total number of students in the sports group) - 63 (students playing at least one game) = 27 students are not playing any of the games.