The equation is 5y-[2*(20-y)]=79.
To solve this equation, y= 17.
The calculation process is as follows: 5y-2*(20-y)=79.
5y-40+2y=79
7y= 1 19
y= 17
Method 2
1, assuming all pairs of 20x5= 100 points.
100-79=2 1.
5+2=7
Wrong question: 2 1 divided by 7=3 (Dao)
Correct question: 20-3= 17 (Dao)
2. Suppose the total error is 20x2=40 points (40 points were deducted, but he got 79 points, with a difference of 79+40= 1 19 points).
There is a difference of 7 points between the right and wrong scores. Correct question: 1 19 divided by 7= 17 (track).