
Things to
remember: • When dealing with probability and permutations, it is important to know if the problem deals with replacement, or without replacement. For example, "with replacement" would be drawing an ace from a deck of cards and then replacing the ace in the deck before drawing a second card. "Without replacement" would be drawing the ace and not replacing it in the deck before drawing the second card. •
Don't forget to use the counting principle for many compound events.
It is fast and easy. 

• Probability
formula:

Where n(S) is the number of elements in the space and n(E) is the number of outcomes in the event. 
Examples: 1. Two cards are drawn at random from a standard deck of 52 cards, without replacement. What is the probability that both cards drawn are queens?
_{ } 2. Mrs. Schultzkie has to correct papers for three different classes: Algebra, Geometry, and Trig. If Mrs. Schultzkie corrects the papers for each class at random, what is the probability she corrects Algebra papers first? There is only one way to correct
Algebra papers
first.
3. A card is drawn from a deck of
standard cards and then replaced in
the deck. A second card is then drawn and replaced. What is
the probability that a queen is drawn each time?

