There are 8 balls in the urn, 3 white and 5 black. What is the probability that 2 balls taken

There are 8 balls in the urn, 3 white and 5 black. What is the probability that 2 balls taken out at random will turn out to be black?

Probability of drawing the first black ball:
p1 = 5/8.
The conditional probability of drawing the second black ball, provided that the first was black:
p2 = 4/7;
The probability that both balls are black by the multiplication theorem:
P = p1 * p2 = 5/8 * 4/7 = 20/56 = 5/14 = 0.357.
Answer: 0.357.