A drawer contains 3 white balls and 6 black balls. Two balls are drawn out of the box at random. What is the probability that they both are black?
TOTAL: 9 balls
Probability that first pick is black= 6/9=2/3
Probability that second pick is black (the first one is taken already, so subtract 1 from numerator and denominator.) = 5/8
Multiply both:5/8 x 2/3=5/12