Your statement is not very clear. If there are correct answers, wrong answers and no answers in 20, three unknowns and two equations are obviously insoluble. If you just press the correct answer and the wrong answer, the result is not an integer, which is obviously wrong.

We can analyze it like this. The single digits of the correct answer can only be 0 and 5, but 5 is an odd number, and it is also wrong to get 4 by subtraction. Then the wrong answer can only be 6 consecutive numbers to get 4 by subtraction. 13*5=65, which means at least 13 is correct. This combination is: 14 * 5 = 70, 16 * 5 = 80, 18 * 5 = 90. The wrong answers are 3 * 2 = 6, 8 * 2 = 16, 13 * 2 = 26. Because the total * * * did 20, so I can only get 14 pairs, 3 mistakes, and 3 unanswered.