Решение задачи N4627 теория вероятностей Пуассона

4627. Radio equipment consists of 1000 parts, each of which can fail during the day 0.002 and does not depend on the state of other elements. Find the probability of failure during the day:
a) only two elements;
b) at least two elements;

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