There are 5 red and 7 white balls in a bag. Two balls are drawn one by one without replacement. Find the probability that first ball is red and second is white.

Answer

N/a

Explanation

Let `A=` event of drawing first ball red,
and `B=` event of drawing second ball white
`:.` Required probability `=P(AnnB)`
`=P(A).P(B//A)`
Now `P(A)=(.^(5)C_(1))/(.^(12)C_(1))=5/12`
After draw of one red ball, remaining balls red `=4` white `=7`
`:. P(B//A)=(.^(7)C_(1))/(.^(11)C_(1))=7/11`
and required probability `=5/12xx7/11=35/132`