Probability is the ratio of the desired outcomes to all possible outcomes. If there are no desired outcomes, the ratio is 0 over all possible outcomes, thus 0. If the event is all possible outcomes, the ratio is all possible outcomes over all possible outcomes, thus 1.
Probability is the ratio of the desired outcomes to all possible outcomes. If there are no desired outcomes, the ratio is 0 over all possible outcomes, thus 0. If the event is all possible outcomes, the ratio is all possible outcomes over all possible outcomes, thus 1.
A decimal would be 400.0 because it is exactly 400. a fraction could be a lot but an easy one would be 400 over 1 which, if you simplify would be 400. with no remainders.
