Make a better score than my students!
Score: 387


string a(string s,int n){return string.Join(s,new string[n+1]);} (64)
int b(int n){bool p=true;for(int i=2;i&lt;n;i++)if(n%i&lt;1)p=false;return n&lt;2?0:b(n-1)+(p?1:0);} (91)
object[]c(object[]l){return l.Where(x=&gt;x!=null).ToArray();} (59)
int d(int n){return(n+1)*n/2;} (30)
char e(char c){return(char)(c&lt;97?c+32:c-32);} (45)
bool f(string s,int n){return s.Length%n&lt;1;} (44)
bool g(string s){return s.SequenceEqual(s.Reverse());} (54)


Total: 387