Question

A committee consists of 9 students two of which are from 1 st year ,3 from 2nd year and 4

from 3rd year .3 students are to be removed at random. What is the chance that

i) The three students belongs to different classes

ii) The two students belongs to the same classes and 3 rd to different class

iii) The 3 belongs to the same class?​

Answer 1

Answer:

2/7.

Step-by-step explanation:

1) 1/729

2) 1/24

3) 1/21

4) 2/7

Solution: Option (4) 2/7

Total cases = 9C3

Favourable cases = 2C1 . 3C1. 4C1

Hence, the required probability = ( 2C1 . 3C1. 4C1) /9C3

= (2. 3. 4)/84

= 24/84

= 2/7.