PROBABILITY C11

A bag contains 6 red balls and 8 blue balls. Two balls are taken from the bag. What is the probability that they are both blue?

Solution

(This is a problem with replacement)

n(R) = 6, n(B) = 8, n(S) = 14

P(B) = n(B)

            n(S)

1st pick = 8/14

2nd pick = 8/14 as well.

P(B) =  6      x    6

          14          14

P(B) =    36    =      4 

             196           49  

Therefore Probability of drawing a blue ball is 4/49     

TRY THIS ..............

A bag contains 10 purple stones and 12 blue stones. Two stones are taken from the bag. What is the probability that they are both blue?