Xiaohong took part in the math contest, and * * * had 20 questions. At that time, it was stipulated that if you answered a question correctly, you would get eight points, if you answered a question wrongly, you would get five points, and if you answered a question wrongly, you would get zero points.

Analysis, if all the answers are correct, it should be 20x8= 160.

Then let's set the answer to question X.

8x-5(20-x)= 12 1

13x=22 1

x= 17

Correct answer 17

Satisfied adoption!