# The grade marks of 50 students of a class are recorded as below

A student of the class is selected at random, what is the probability that the selected student has obtained grade A?

$

{\text{A}}{\text{. }}\dfrac{4}{{25}} \\

{\text{B}}{\text{. }}\dfrac{{16}}{{50}} \\

{\text{C}}{\text{. }}\dfrac{4}{{50}} \\

{\text{D}}{\text{. }}\dfrac{8}{{25}} \\

$

Last updated date: 24th Mar 2023

•

Total views: 309k

•

Views today: 2.86k

Answer

Verified

309k+ views

**Hint:**Here, we will be using the general formula for the probability of occurrence of an event, i.e., $P(A) = \dfrac{{{\text{Number of favorable outcomes}}}}{{{\text{Total number of possible outcomes}}}}$

**Complete step by step answer:**

Given, Total number of students in a class$ = 50$

According to the given data in the table, we can say that

Number of students having grade C$ = 13$,

Number of students having grade B$ = 17$,

Number of students having grade A$ = 8$

And, Number of students having grade A+$ = 12$

As we know that the general formula for probability is given by

Probability of occurrence of an event $ = \dfrac{{{\text{Number of favorable outcomes}}}}{{{\text{Total number of possible outcomes}}}}$

Here, the favorable event is that the selected student has obtained grade A.

So, Number of favorable outcomes $ = $ Number of students who has obtained grade A$ = 8$

Total number of possible outcomes $ = $ Total number of students in a class$ = 50$

Therefore, Required probability $ = \dfrac{8}{{50}} = \dfrac{4}{{25}}$

**Hence, the probability that the selected student has obtained grade A is $\dfrac{4}{{25}}$. So, Option (A) is correct.**

**Note:**In these types of problems, the favorable event is the event whose probability is asked to find out. In this particular problem, extra data is also provided in the question itself (number of students who have obtained grades C, B and A+) which is not being used anywhere to get to the answer.

Recently Updated Pages

Calculate the entropy change involved in the conversion class 11 chemistry JEE_Main

The law formulated by Dr Nernst is A First law of thermodynamics class 11 chemistry JEE_Main

For the reaction at rm0rm0rmC and normal pressure A class 11 chemistry JEE_Main

An engine operating between rm15rm0rm0rmCand rm2rm5rm0rmC class 11 chemistry JEE_Main

For the reaction rm2Clg to rmCrmlrm2rmg the signs of class 11 chemistry JEE_Main

The enthalpy change for the transition of liquid water class 11 chemistry JEE_Main

Trending doubts

Ray optics is valid when characteristic dimensions class 12 physics CBSE

Fill in the blanks A 1 lakh ten thousand B 1 million class 9 maths CBSE

What is the Full Form of PVC, PET, HDPE, LDPE, PP and PS ?

Alfred Wallace worked in A Galapagos Island B Australian class 12 biology CBSE

Imagine an atom made up of a proton and a hypothetical class 12 chemistry CBSE

Differentiate between homogeneous and heterogeneous class 12 chemistry CBSE

How do you define least count for Vernier Calipers class 12 physics CBSE

Why is the cell called the structural and functional class 12 biology CBSE

A 30 solution of H2O2 is marketed as 100 volume hydrogen class 11 chemistry JEE_Main