Addition Rule of Probability

If there are two events A and B having probability as P(A) and P(B) respectively. Then, according to the addition rule of probability, the combined probability will be calculated by the formula given below.

  P(AUB) = P(A) + P(B) – P(A∩B)

Probability is the estimation of the possibility of random events happening, and its value ranges from 0 to 1. The probability of a sure event is always one, and the event that will never occur has a probability of zero. You may have also wondered how weather stations predict that it will rain today and how a cricket team’s winning and losing is made. Probability theory helps in finding answers to all such questions. Probability deals with the chances of occurrence of random experiments.

Probability of getting an outcome is defined as the ratio of the number of times the event is occurring to the total number of trials.  

P(A) = (Number of times event A is occurring/Total number of Trials)

Let’s try this formula to calculate the probability of all the possible outcomes of rolling a single die. Suppose you roll a die, there are six possible outcomes. They are 1, 2, 3, 4, 5, and 6. The probability of getting 1 on die is P(1) = 1/6. Similarly, the probability of getting 2, 3, 4, 5, and 6 is also 1/6.