# Chapter 25 – Probability – R S Aggarwal Solutions for class 8

We must have understanding of the terms and concepts given below:

Experiment: An activity that can result in some well-defined outcomes is experiment. For ex. tossing a coin is an experiment.

Random experiment: It is an experiment in which all possible outcomes are known but not sure about specific outcome.

Event: The possible outcomes of an experiment is an event

Equally likely events: outcomes of an experiment are equally likely if each has the same chance of occurring

 Number of favorable outcomes    Total number of outcomes

Probability of occurrence of an event: Suppose E is any event. Then Probability of occurrence of E is given by

P (E) =

Some Experiments and their outcomes:

(a) Tossing a coin: when we toss a coin, all possible outcomes are Head (H) and Tail (T)

(b) Tossing two coins: when we toss two coins, all possible outcomes are {HH, HT, TH, TT}

(c) Throwing a die: when we throw a die, all possible outcomes are {1, 2, 3, 4, 5, 6}

(d) Drawing a card from a well shuffled deck of 52 cards:

Total number of cards in a deck = 52 cards

Red cards = 26 and Black cards = 26

There are 4 suits namely spades, clubs, hearts and diamonds each having 13 cards

Cards of spades and clubs are black cards and cards of heart and diamond are red cards.

Kings, queens and jacks are face cards. Thus there are 12 face cards in total.