The maximum is $3$ since any group of $7$ at most $3$ are grey. 
Joseph has $$100$$ mice. Each of them is either white or grey. At least one of the mice is grey, and out of any seven of Joseph\textquotesingle s mice at least four are white. How many grey mice does Joseph have at the most? 

1: $$1$$ 
2: $$3$$ 
3: $$93$$ 
4: $$97$$ 
5: $$99$$ 