if there can be no more than 5 students, then anything less than 5 students will suffice. However we don’t want any left over ones cause we don’t want that one kid sitting alone during lunch so we can simply put <u><em>4 into each group.</em></u>
The probability of drawing the initial Jack is 4 out of 52 as there are 4 Jacks in deck of 52 cards. Since you are not replacing the Jack the Deck now has 51 cards and 3 Jacks making that 3 out of 51