How do you get 100 by using 9 exactly 4 times

Depends on what you mean by "using". If catenation is allowed, then we can start with 99 (so 2 9s get used up). Then add 1 to this in the form of .

answer: huh

step-by-step explanation:

answer: all of the odd numbers were opened

the first person was the one that was opening all of the lockers. since one is odd, this causes all of the odd number lockers to be opened in the end.