Probability

Definition of Probability :

The extent to which an event is likely to occur, measured by the ratio of the favourable cases to the whole number of cases possible.

Examples :

1.Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5?

Explanation :

Here ,S = { 1 ,2,3,4……,19,20}

Let E = event of getting a multiple of 3 or 5 = { 3,6,9,12,15,18,5,10,20}

P(E) = n(E) / n(S) = 9/20

2. What is the probability of getting head when tossing a coin.

Sample Space = {H, T}

Number of possible outcomes = 2

Number of favorable outcomes = 1
(because of only one head)

=> Probability of getting head = Number of favorable outcomes / Total number of possible outcomes.

= 1212

Formula of Probability :

Number of favorable outcomes / Total number of possible outcomes.