Question

The following table shows the blood groups of 40 students of a class.

$\begin{array}{ccccc}\text{Blood group}& A& B& O& AB\\ \text{Number of students}& 11& 9& 14& 6\end{array}$

One student of the class is chosen at random. What is the probability that the chosen studet has blood group (i) O? (ii) AB?

Answer 1

ANSWER:
Total number of students = 40
(i) Number of students with blood group O = 14
Let E 1 be the event that the selected student's blood group is O.
∴ Required probability = P ( E 1 ) = $\frac{14}{40}$ = 0.35
(ii) Number of students with blood group AB = 6
Let E 2 be the event that the selected student's blood group is AB.
∴ Required probability = P ( E 2 ) = $\frac{6}{40}$ = 0.15