Probability — Class 11 Mathematics

Core Concepts

For an equally likely finite sample space, P(E)=n(E)/n(S). An event is a collection of outcomes. The complement satisfies P(E′)=1−P(E).

Worked Examples

For one fair die, the probability of getting an even number is 3/6=1/2.

From a standard deck of 52 cards, P(a heart)=13/52=1/4.

If P(A)=0.7, then P(A′)=0.3.

Explained MCQs

1. Probability always lies between 0 and 1.
2. For a fair coin, P(head)=1/2.
3. If an event is certain, its probability is 1.

Practice

1. Find the probability of drawing an ace from a standard deck.
2. A die is thrown once. Find P(number greater than 4).
3. If P(A)=3/8, find P(A′).