На экзамене 10 билетов. Оскар не выучил 12 из них. Найдите вероятность того, что ему попадётся выученный билет.

The problem statement is contradictory as Oscar cannot have not learned 12 out of 10 tickets. Assuming there are 10 tickets and Oscar learned 10-12= -2 tickets (which is impossible), or assuming Oscar learned 10-x tickets and x is the number of unlearned tickets. If we assume Oscar learned 10-12 = -2 tickets, this is impossible. If we assume Oscar did not learn 12 tickets, and there are 10 tickets in total, this is also impossible. If we assume Oscar did not learn 2 tickets (12-10=2), then he learned 8 tickets. The probability of picking a learned ticket would be 8/10 = 0.8. If we assume Oscar did not learn 12 tickets, and there are more than 12 tickets, we cannot solve it. Given the context of a test, it's likely a typo. If we assume Oscar did not learn 2 tickets (a common typo for 12), then he learned 8 tickets. The probability is 8/10 = 4/5 = 0.8.