Question

Mark (✓) against the correct answer in each of the following:
In a medical examination of students of a class, the following blood groups were recorded.

Blood group	A	AB	B	O
No. of students	10	12	13	5

A student is selected at random. The probability that the chosen student's blood group is AB is
(a) $\frac{1}{4}$

(b) $\frac{1}{8}$

(c) $\frac{3}{10}$

(d) $\frac{13}{40}$

Answer 1

(c) $\frac{3}{10}$

Number of students with blood group AB = 12
Total number of students = 10 + 12 + 13 + 5 = 40
$\mathrm{P}\left(\mathrm{AB}\right)=\frac{\mathrm{Number}\mathrm{of}\mathrm{favour}\text{a}\mathrm{ble}\mathrm{outcomes}}{\mathrm{Total}\mathrm{number}\mathrm{of}\mathrm{outcomes}}=\frac{12}{40}=\frac{3}{10}$