# Basic Probability

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Probability is the chance that something will happen; there are two kinds of probability, theoretical and experimental.
Experimental probability = numberofeventoccurences / (Total number of trials)
Theoretical probability = (Number of favourable outcomes) / (Total number of outcomes)
Example 1: Which of the following is an experiment?
1. Tossing a coin
2. Rolling a single 6 sided die
3. Choosing a ball from a jar
4. All of the above
Answer: d
Example 2: A number from 1 to 13 is chosen at random. What is the probability that the selected number is a prime number?
Answer: Prime numbers from 1 to 13 are 2, 3, 5, 7, 11, 13.
Number of prime numbers = 6
Probability of selecting a prime number = 613
Example 3: What is the probability of drawing a red colored ace from a set of cards ?
Answer:
Total number of cards in a set = 52
Total number of red colored cards = 13 x 2 = 26
Number of ace’s in red colored cards = 2
probability of drawing an ace from a red colored card = 226 = 113