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What is the probability of getting 7 on rolling a die?

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  • Last Updated : 12 Oct, 2021

Probability is a part of math which deals with the possibility of happening random events. It is to predict how likely the events will occur or the event will not occur. The probability of happening an event is between 0 and 1 only and can also be written in the form of a percentage or fraction. The probability of event B is often written as P(B). Here P indicates the possibility and B indicate the happening of an event. Similarly, the probability of any event is often written as P(). When the end result of an event is not confirmed we use the probabilities of certain consequences—how likely they occur or what are the chances of their occurring. 

The unpredictability of ‘probably’ etc., can be calculated numerically by means of ‘probability’ in many cases.

Though probability started with a bet, it has been used carefully in the fields of Physical Sciences, Commerce, Biological Sciences, Medical Sciences, Weather Forecasting, etc.

To understanding probability we take an example as rolling a dice:

There are six possible outcomes— 1, 2, 3, 4, 5, and 6.

The probability of getting any of the numbers is 1/6. As the event is an equally likely event so there is same possibility of getting any number in this case it is either 1/6 or 50/3%.

Formula of Probability

Probability of an event = {Number of ways it can occur} ⁄ {Total number of outcomes}

P(A) = {Number of ways A occurs} ⁄ {Total number of outcomes}

Types of Events

Equally Likely Events: Rolling a dice the probability of getting any of the numbers is 1/6. As the event is an equally likely event so there is same possibility of getting any number in this case it is either 1/6 in fair dice rolling.

Complementary Events: Possibility of only two outcomes which is an event will occur or not. Like a person will eat or not eat the pizza, buying a bullet or not buying a bullet, etc. are examples of complementary events.

Question: What is the probability of getting 7 on rolling a die?

Answer:

If we are tossing a unbiased die then 7 is not an event in sample space ,so the 

probability of occurrence of this event is zero.

We know that,

A die only has dots or numbers from 1 to 6, i.e., 1,2,3,4,5,6.

∴ The probability of getting number 7 = 0.

Similar Questions

Question 1: What is the probability of rolling one die and getting a 6?

Answer:

In rolling a dice, the sample space S = {1,2,3,4,5,6} 

n(S) = 6

Let A be the event of getting the number 6.

A = {6}  

n(A) = 1

P(A) =  n(a) ⁄ n(s) = 1⁄6

Question 2: What is the probability of rolling one die and getting a 5?

Solution:

In rolling a dice, the sample space S = {1,2,3,4,5,6} 

n(S) = 6

Let A be the event of getting the number 5.

A = {5}  

n(A) = 1

P(A) =  n(a) ⁄ n(s) = 1⁄6

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