The table given below shows the marks obtained by 30 students in a tes

1.	The table given below shows the marks obtained by 30 students in a test.Marks (Class interval)1-1011-2021-3031-4041-50Number of students (Frequency)710643Out of these students, one is chosen at random. What is the probability that the marks of the chosen student(i) are 30 or less?(ii) are 31 or more?(iii) lie in the interval 21 – 30?
Answer» It is given that Total number of students = 30 (i) We know that Probability that the marks of the chosen students are 30 or less = (7 + 10 + 6)/ 30 So we get Probability that the marks of the chosen students are 30 or less = 23/30 (ii) We know that Probability that the marks of the chosen students are 31 or more = (4 + 3)/30 So we get Probability that the marks of the chosen students are 31 or more = 7/30 (iii) We know that Probability that the marks of the chosen students lie in the interval 21 – 30 = 6/30 So we get Probability that the marks of the chosen students lie in the interval 21 – 30 = 1/5

The table given below shows the marks obtained by 30 students in a test.Marks (Class interval)1-1011-2021-3031-4041-50Number of students (Frequency)710643Out of these students, one is chosen at random. What is the probability that the marks of the chosen student(i) are 30 or less?(ii) are 31 or more?(iii) lie in the interval 21 – 30?

Answer»

It is given that

Total number of students = 30

(i) We know that

Probability that the marks of the chosen students are 30 or less = (7 + 10 + 6)/ 30

So we get

Probability that the marks of the chosen students are 30 or less = 23/30

(ii) We know that

Probability that the marks of the chosen students are 31 or more = (4 + 3)/30

So we get

Probability that the marks of the chosen students are 31 or more = 7/30

(iii) We know that

Probability that the marks of the chosen students lie in the interval 21 – 30 = 6/30

So we get

Probability that the marks of the chosen students lie in the interval 21 – 30 = 1/5