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# In a medical examination of students of a class, the following blood groups are recorded:

Blood group A AB B O

Number of students 10 13 12 5

A student is selected at random from the class. The probability that he/she has blood group B, is:

a. 1/4

b. 13/40

c. 3/10

d. 1/8

**Solution:**

It is given that

Total number of students in a medical examination n(S) = 40

Number of students who have B blood group n(E) = 12

We know that

Probability that he/she has blood group B = n(E)/n(S)

Substituting the values

= 12/40

= 3/10

Therefore, the probability that he/she has blood group B is 3/10.

**✦ Try This: **In a survey of 125 children aged 10-15 months, it was found that 21 liked to eat potato chips. If a child is selected at random, the probability that he/she does not like to eat potato chips is :

**☛ Also Check:** NCERT Solutions for Class 9 Maths Chapter 14

**NCERT Exemplar Class 9 Maths Exercise 14.1 Problem 27**

## In a medical examination of students of a class, the following blood groups are recorded: Blood group A AB B O Number of students 10 13 12 5. A student is selected at random from the class. The probability that he/she has blood group B, is: a. 1/4, b. 13/40, c. 3/10, d. 1/8

**Summary:**

In a medical examination of students of a class, the following blood groups are recorded. A student is selected at random from the class. The probability that he/she has blood group B, is 3/10

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