Решение задачи N1379 теория вероятностей Лапласа

1379. Stamping of metal terminals for connecting plates gives 20% rejection. Determine the probability that of the 400 terminals selected at random, the corresponding standard will be:
a) exactly 300 pieces;
b) no less than 310 and not more than 330 pieces.

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