There are 5 people who can be guards, 2 will be guards. Since each person has the same chance of becoming a guard, each person has a 2/5 chance of being a guard which makes it unlikely for Diana to become a guard.
400÷4/7=700 you want divide the totals amount of lemonade among pitchers that only hold 4/7 of the lemonade. if the container held 1 qt, you would divide the total by 1