Решение задачи N1081 теория вероятностей Лапласа

1081. The power plant serves a network with 16,000 light bulbs, each of which can be switched on in a certain period of time with a probability of 0.6. Calculate the probability that during this time period will be included:
a) the number of bulbs, equal to the most probable number included;
b) at least 9000 light bulbs.

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