Question

A bag contains 6 white and 4 black balls. Two balls are drawn at random. Find the probability that they are of the same color.

Answer 1

342

Q:

A bag contains 6 white and 4 black balls .2 balls are drawn at random. Find the probability that they are of same colour.

A) 1/2B) 7/15C) 8/15D) 1/9

Answer:   B) 7/15 

Explanation:

Let S be the sample space

 

Then n(S) = no of ways of drawing 2 balls out of (6+4) =10C210C2 10 =10*92*110*92*1 =45

 

Let E = event of getting both balls of same colour

 

Then,n(E) = no of ways (2 balls out of six) or (2 balls out of 4)

 

                =6C2+4C26C2+4C2 = 6*52*1+4*32*16*52*1+4*32*1= 15+6 = 21

 

Therefore, P(E) = n(E)/n(S) = 21/45 = 7/15