Question

The marks of 100 students (out of 80) in English speaking skills was recorded as follows :

Marks 0-20 21-39 40-60 61-80

No. of students 18 19 23 20

If the passing marke are 50%, then find the probability that the student choosen at random :

(a) got the passing marks.

(b) failed to get the passing marks.

(c) got below 21 marks.

Answer 1

Students got the passing marks were43
Students don't got the passing marks were43
Students got below 21 were18

Answer 2

Answer:

A - 0.43

B - 0.37

C - 0.18

Step-by-step explanation:

We are given that,

Total number of marks = 80

Total number of students = 100

Now, the passing marks are 50% of the total marks.

So, the passing marks = $\frac{50}{100}\times 80$ = 40.

Thus, we have,

(A) Number of students who got the passing marks = 23 + 20 = 43

The probability of students getting passing marks = $\frac{43}{100}$ = 0.43

(B) Number of students failing to get the passing marks = 18 + 19 = 37

The probability of students failed to get the passing marks = $\frac{37}{100}$ = 0.37

(C) Number of students who got marks below 21 = 18

The probability of students who got below 21 marks = $\frac{18}{100}$ = 0.18