A bag contains 12white and 18black balls. 2balls are drawn in succession. What is the probability that first is white and second is black?  Options.
A) 31/145  B) 36/145  C) 32/145  D) 36/147  E) None
The probability that first ball is white:   =12C130C1=12C130C1   =1230=1230   =25=25   Since, the ball is not replaced; hence the number of balls left in bag is 29.   Hence, the probability the second ball is black:   =18C129C1=18C129C1   =1829=1829   Required probability,   =(25)×(1829)=(25)×(1829)   =36/145   36/145
<result>B</result>
A bag contains 12white and 18black balls. 2balls are drawn in succession. What is the probability that first is white and second is black?