SOLUTION: a bag contains 4 red and 6 green identical balls. if two are drawn together at random from the bag, find the probability that they are of the same colour

Algebra ->  Probability-and-statistics -> SOLUTION: a bag contains 4 red and 6 green identical balls. if two are drawn together at random from the bag, find the probability that they are of the same colour      Log On


   

Question 778589: a bag contains 4 red and 6 green identical balls. if two are drawn together at random from the bag, find the probability that they are of the same colour
Answer by psbhowmick(878) About Me  (Show Source):
You can put this solution on YOUR website!
Total no. of ways in which 2 balls can be selected out of 10 is 10C2 = 45.

Total number of ways in which 2 red or 2 green balls can be selected is 4C2 + 6C2 = 6 + 15 = 21

So the probability of picking up 2 balls of the same color = 21/45 = 7/15