Решение задачи N2861 теория вероятностей

2861. In a group of 30 students in the control work received: “Excellent” - 8 students, “Good” rating - 10 students, “Satisfactory” rating - 9 students, “Unsatisfactory” rating - 3 students. What is the likelihood that three students called to the blackboard coped with the test?

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