Making of speech lottery

Hehe, it should be a primary school question, so probability theory and mathematical statistics should not consider all kinds of variables, just solve the simplest probability problem:

The probability of the first lottery is 16 familiar questions divided by the total number of 20 questions, which is 16/20, and the score is about 4/5.

The second question is the same: because the question 10 is selected, the remaining question 10 is selected, and two unfamiliar contents are selected, leaving 4-2=2 unfamiliar contents, so the probability is 10-2=8 familiar questions divided by the total number of remaining questions 10, and 8 is obtained.

So the conclusion is that the probability of the first lottery is 80%, and 1 1 lottery is still 80%.

In fact, such a simple question is not easy for the landlord to do by himself.