In a medical examination of students of a class , the following blood groups are recorded :

From this class , a student is chosen at random . What is the probability that the chosen student has blood group AB ?

In a medical examination of students of a class, the following blood groups are recoreded.

A student is selected at random from the class. The probability that he/she has blod group B, is

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

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

The following table shows the blood groups of 60 students of a class :
$\left|\begin{array}{c}\text{Blood groups A B O AB}\\ \text{Number of students 16 12 23 9}\end{array}\right|$
One student of the class is chosen at random. What is the probability that the chosen student has blood group?
$\text{(i) O (ii) AB (iii) A (iv) B}$

There are 35 students in a class of whom 20 are boys and 15 are girls.
From these students one is chosen at random. What is the probability that the chosen student is a (i) boy, (ii) girl?

There are 35 stdents in a class, of whom 20 are boys and 15 are girls. From these students, one is chosen at random. What is the probability than the chosen student is a (i) boy? (ii) girl?

The marks obtained by 90 students of a school in mathematics out of 100 are given as under :

From these students , a student is chosen at random .
What is the probability that the chosen student
(i) gets 20% or less marks ? (ii) gets 60% or more marks ?

The table given below shows the months of birth of 36 students of a class :

A student is chosen at random from the class . What is the probability that the chosen student was born in October ?

Marks obtained by 90 students of class IX in a test are given below:

Out of these students, one is chosen at random. Find the probability that the chosen student obtains
less than 20% marks

Marks obtained by 90 students of class IX in a test are given below:

Out of these students, one is chosen at random. Find the probability that the chosen student obtains more than 80% marks

Marks obtained by 90 students of class IX in a test are given below:

Out of these students, one is chosen at random. Find the probability that the chosen student obtains more than 60 %marks