Definition
Theoretical Probability is the ratio of the number of favorable outcomes to the total possible outcomes of an event.
Expressing probability as a formula:
Information about a standard deck of cards:
A standard deck of cards has four suits: hearts, clubs, spades, diamonds. Each suit has thirteen cards: ace, 2, 3, 4, 5, 6, 7, 8, 9, 10, jack, queen, and king. Thus the entire deck has 52 cards total.
(a) Picture card (J, Q, and K)
In a standard deck, there are 4 Jacks, Queens, and Kings. Hence, the probability of J, Q, and K are:
Probability as a fraction:
In decimal:
Percent:
(b) 9 or 10
There are 4 cards labeled 9 and 10 each.
Probability as a fraction:
In decimal:
In percent:
(c) 2 of heart
In a standard deck of cards, there are only one 2 of hearts.
Probability as a fraction:
In decimal:
In percent: