Question

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 :

(A) 1/4

(B) 13/40

(C) 3/10

(D) 1/8

Answer 1

(C) 3/10

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

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

∴ Probability that he/she has blood group B = n(E)/n(S) = 12/40 = 3/10

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