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

Blood group A B O AB

Number of students 11 9 14 6

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

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Solution

Total number of students = 40
(i) Number of students with blood group O = 14
Let E₁ be the event that the selected student's blood group is O.

∴ Required probability = P(E₁) = $\frac{14}{40} = 0.35$

(ii) Number of students with blood group AB = 6

Let E₂ be the event that the selected student's blood group is AB.

∴ Required probability = P(E₂) = $\frac{6}{40} = 0.15$

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Similar questions

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

$\begin{matrix} Blood group & A & B & O & A B Number of students & 11 & 9 & 14 & 6 \end{matrix}$

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

Q. The blood groups of 30 students of a class were recorded as under:

Blood Group	A	B	AB	O
No. of students	9	11	4	6

If a student of this class is chosen at random, what is the probability that the chosen student has blood group
(i) O?
(ii) A?
(iii) AB?

Q. In a medical examination of 40 students of a class, the following blood groups were recorded:

Blood group	A	B	AB	O
No. of students	11	15	9	5

From this group, a student is chosen at random. What is the probability that the chosen student's blood group is B?
(a)

\frac{3}{5}

(b)

\frac{5}{8}

(c)

\frac{3}{5}

(d)

\frac{8}{3}

Q. 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) $\frac{13}{40}$

Q.

Blood group

Number of students

A

9

B

6

AB

3

O

12

Total

30

The above frequency distribution table represents the blood groups of 30 students of a class. Use this table to determine the probability that a student of this class, selected at random, has blood group AB.

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The following table shows the blood groups of 40 students of a class. Blood group A B O AB Number of students 11 9 14 6 One student of the class is chosen at random. What is the probability that the chosen student's blood group is (i) O? (ii) AB?

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

Blood group A B O AB

Number of students 11 9 14 6

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