Probability

Things you should know:

• Two events can't happen at the same time when they are mutually exclusive.
• Formulas you need to know: P(A or B) = P(A) + P(B) - P(A & B). P(A or B) = P(A) + P(B).

Example 1: If you are given a standard 52 deck of cards, what is the probability that you will end up with a red card?

• Since half the deck is red that means you have 26 red cards.
• Your answer would be: 26/52 = 1/2.

Example 2: If you are given a standard 52 deck of cards, what is the probability that you will end up with a queen?

• Things you must know: four queens in a deck.
• Since it is out of 52, you answer will be: 4/52.
• That reduces to 1/13.
• Final answer: 1/13.

Example 3: What is the probability to get a red spade?

• Spades aren't red. They are black.
• Answer: 0/52 = 0.

Amber :)