Question

The marks obtained (out of 80 marks) by 40 students in a test of mathematics are given in the following table:


Marks obtained


0-20


20-30


30-40


40-50


50-60


60-70


70-80

No. of students
3
2
5
8
6
9
7

Find the probability of a student, chosen at random, getting
Less than 40 marks
50 or more marks ​

Answer 1

Answer:

Step-by-step explanation:

I first case:-

Let, event A be the probablity of choosing a student who scored less than 40 marks..

No. Students that scored less than 40 marks = n(E)= 10

Total no. Of students = n(S)= 40

P(A)= n(E)/n(S)

= 10/40

= 1/4