Solution of problem N4540 probability theory

Solution of problem N4540 probability theory

4540. There are 10 balls in the urn: 6 white and 4 black.
a) Two balls are taken out of the urn at the same time. Find the probability that both balls are white?
b) What event, provided that two balls are taken out of the urn at the same time, is more likely: A - "balls of white color", B - "balls of different colors"?

Additional information:

Detailed solution. Decorated in Microsoft Word 2003 (Quest decided to use the formula editor)