# Probability

likely to occur as the other.

For example, when a coin is tossed, both outcomes H and T are equally likely to appear. Thus H and T are equally likely outcomes. Similarly, when we throw a die then the outcomes, 1, 2, 3, 4, 5 and 6 are equally likely.

Favourable outcomes: The outcomes which ensure the occurrence of an event are called favourable outcome of that event.

For example, suppose experiment is throwing a die and event is getting even number, then favourable outcomes are 2, 4 and 6.

Odds in favour or against of occurrence of event: If E and E¯¯¯ are complementary events, then the ratio P(E) : P( E¯¯¯) is called as odds in favour of occurrence of event Ewhile the ratio P( E¯¯¯) : P(E) is called as odds against the occurrence of event E.

For example, suppose experiment is throwing a pair of die and event E is getting doublet.

Then, odds in favour of occurrence of E=P(E)P(E¯¯¯)=6363036=630=15

Odds against occurrence of E=P(E¯¯¯)P(E)=3036636=306=5

Playing cards: The details of playing card having 52 cards are as: 