Assuming that everything he did was right, he should get 20* 10=200 points, which is 200- 136=64 points more than the actual situation.

And because the wrong one is 20+ 12=32 points less than the first one,

So Zhang Hua made 64/32=2 wrong methods, so he made 10-2=8 correct methods.

Also, the score of an.d is (208-64)/2=72 (points).

Assuming that everything he did was right, he should get 20* 10=200 points, which is 200-72= 128 points more than the actual situation.

And because the wrong one is 20+ 12=32 points less than the first one,

So an.d made the mistake of 128/32=4, so he made the mistake of 10-4=6 (Tao).