Question

Class 9th
Mathematics
Chapter 15 - Probality
Formulas Needed . Give 1 example for each Formuals

Note : Don't copy, Don't spam .

Quality answer with good explanation will be Brainliest .​

Answer 1

Answer:

Probability Range 0 ≤ P(A) ≤ 1

Rule of Addition P(A∪B) = P(A) + P(B) – P(A∩B)

Rule of Complementary Events P(A’) + P(A) = 1

Disjoint Events P(A∩B) = 0

Independent Events P(A∩B) = P(A) ⋅ P(B)

Conditional Probability P(A | B) = P(A∩B) / P(B)

Bayes Formula P(A | B) = P(B | A) ⋅ P(A) / P(B)

Step-by-step explanation:

Example 1: What is the probability that a card taken from a standard deck, is an Ace?

Solution:

Total number of cards a standard pack contains = 52

Number of Ace cards in a deck of cards = 4

So, the number of favourable outcomes = 4

Now, by looking at the formula,

Probability of selecting an ace from a deck is,

P(Ace) = (Number of favourable outcomes) / (Total number of favourable outcomes)

P(Ace) = 4/52

= 1/13

So we can say that the probability of getting an ace is 1/13.

Answer 2

The basic formula used in the chapter of Probability is as follows:

$\sf{\implies\:Probability=\dfrac{Favourable\:Outcomes}{Total\:Outcomes}}$

In a more simplified format, it can be written as:

$\sf{\implies\:P(E)=\dfrac{FE}{TE}}$

The formula can be explained as shown below:

Probability of an event refers to the frequency of the favourable event out of the total number of events. The major abbreviations used are:

✳ P(E) = Probability of an Event

✳ FE = Favourable events

✳ TE = Total events

Example

Q. Two proper coins are tossed once. Find the probability of getting an outcome of HH.

A. Each coin will have a head and a tail each meaning that all the possible outcomes will be as follows:

➡ TT, HH, HT, TH

That is total number of outcomes is 4.

Now, the favourable event asked in the question is HH and its frequency is 1.

Applying the probability formula:

$\sf{\implies\:P(E)=\dfrac{FE}{TE}}$

$\sf{\longrightarrow\:P(HH)=\dfrac{1}{4}}$

The probability of getting two heads is henceforth 1/4.

BASIC DEFINITIONS:

✳ Probability refers to experimentation of different events and helps to measure certainty and uncertainty along with the values in between them.

✳ Probability of an event always lies between 1 and 0 whereas the probability of a sure event is 1 and and an impossible event is 0.

Example

➡ Probability of the Sun rising in the east = 1 (Sure event)

➡ Probability of getting HH when a single coin is tossed = 0 (Impossible event)