Assuming everything is right, 25×8=200.

The extra 200-72= 128 means that the penalty is 128 ÷ (8+4) = 10. ...

The remainder of this 8 points is exactly the score for doing a problem correctly.

Explain that one question in the previous calculation was correctly answered, and one question was not done, so points should be deducted.

So I did the right thing; 25- 10- 1= 14

Error: 10.

Incomplete: 1 channel