Question

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:

Options

• `1/4`

• `13/40`

• `3/10`

• `1/8`

Answer 1

`bb(3/10)`

Explanation:

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`.