Question

Example 2 :
The percentage of marks obtained by student in the monthly unit tests are given below :

1•Unit test I percentage of marks obtained 58
•Unit test II percentage of marks obtained 74
•Unit test III percentage of marks obtained 76
•Unit test IV percentage of marks obtained 62
•Unit test V percentage of marks obtained 85

Find the probability that the students gots:
i) a first class, i.e. atleast 60% marks.
ii) marks between 70 % and 80% .
iii) a distinction, i.e. 75% or above.
iv) less than 65% marks ​

Answer 1

Percentage of marks obtain in
unit test
I
I
I
I
I
I
I
V
V
Percentage of marks obtained
69
71
73
68
76
(i) Probability of getting more than 70% marks (m)= In unit test II, III,V=3 Total unit test (n)=5
∴
probability P(A)=
m
n
=
3
5
=
0.6
(ii) Getting less than 70% marks =units test I and IV
∴
m
=
2
Total unit test (n)=5
∴
Probablility P(A)=
m
n
=
2
5
=
0.4
(iii) Getting a distinction = In test V (76 of marks)
∴
m
=
1
Total unit test (n)=5
∴
Probablility P(A)=
m
n
=
1
5
=
0.2

Answer 2

Answer:

Step-by-step explanation:

Total no. of unit tests =5

Number of tests in which the student scored more than 70% marks =3

Therefore,

Probability that a student gets more than 70% marks =  

Total no. of tests

No. of tests in which the student scored more than 70% marks

​

 

=  

5

3

​

=0.6

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SIMILAR QUESTIONS

star-struck

400 students of class X of a school appeared in a test of 100 marks in the subject of social

studies and the data about the marks secured is as below :

           Marks

         secured Number of

Students

           0−25      50

         26−50     220

         51−75     100

       Above 75       30

Total number of students     400

If the result card of a student he picked up at random, what is the probability that the student has secured more than 50 marks.