Discussion Forum



1)

The bad contains 5 red balls, 3 black balls and 4 white balls . Three balls are drawn at random . The probability that they are not of same colour is 


A) $\frac{37}{44}$

B) $\frac{31}{44}$

C) $\frac{21}{44}$

D) $\frac{41}{44}$

Answer:

Option D

Explanation:

We have,

 5 red balls, 3 black balls , 4 white balls

Total number of balls =(5+3+4)=12

Three balls are drawn= $ ^{12}C_{3}=220$

 Three balls are drawn of same colour

    $^{5}C_{3}+^{3}C_{3}+^{4}C_{3}=10+1+4=15$

 Probability of are not same colour 

   =1- Probability of same colour

  =$1-\frac{15}{220}=1- \frac{3}{44}=\frac{41}{44}$