Решение задачи N1198 теория вероятностей Лапласа

1198. The reading room of the Institute is designed for 300 students, each with a probability of 0.2 takes an English-Russian dictionary. How many such dictionaries should be on the subscription, so that with a probability of 0.85 it was possible to provide everyone?

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