Question

There are two bags containing white and black balls. In the first bag, there are 8 white and 6 black balls and in the second bag, there are 4 white and 7 black balls. One ball is drawn at random from one of the two bags chosen at random. Find the probability of this ball being black.

Answer 1

47/11 is the probability

Answer 2

total no. of balls in both bags = no. of possible outcomes = 25 { total balls }
total no. of favourable outcomes = 13 { no. of black balls }
p( black ball ) =
$\frac{no. \: \: of \: favourable \: outcomes}{total \: no. \: of \: possible \: outcomes}$
=
$\frac{13}{25}$