Probability Formula
If a random experiment is conducted in which there are n elementary events, all equally likely, and A is an event, the probability of event A is:
Examples
Find the probability of tossing two coins simultaneously and obtaining two heads.
Possible outcomes: {hh, ht, th, tt}.
Favorable outcomes: 1.
In a deck of 40 cards, if one card is removed, find the probability of an Ace (P(Ace)) being drawn and the probability of a Diamond (P (Diamond)) being drawn.
Possible outcomes: 40.
Favorable outcomes of aces: 4.
Favorable outcomes of diamonds: 10.
Calculate the probability of rolling a die and obtaining:
1 An even number.
Possible outcomes: {1, 2, 3, 4, 5, 6}.
Favorable outcomes: {2, 4, 6}.
2 A multiple of three.
Favorable outcomes: {3, 6}.
3 A result greater than 4.
Favorable outcomes: {5, 6}.
