Решение задачи N4125 теория вероятностей Лапласа

4125. The store receives goods, 80% of which are of the first grade. How many products need to be taken so that with a probability of 0.997 one could argue that the frequency of products of the first grade will be in the range from 0.75 to 0.85?

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