20 points for a correct question, and 0 points for a wrong deduction 10. Each of them will do 10, and * * * will get 100.

Zhang Hong scored 60 points more than Li Chao. Zhang Hong and Li Chao each answered several questions correctly.

Li Chao's score: (100-60)÷2=20.

Zhang Hong's score is: 100-20=80.

Set one of them as topic X.

20x-30y=80

20x-30z=20

30(z-y)=60

z-y=2

40x-30(y+z)= 100

4x-3(y+z)= 10

Divide both sides by two.

2x-3(y+z)/2=5

( 1) y+z=6

2x-9=5

x=8

z=4

Y=2 (uncorrelated)

(2)y+z= 10

2x- 15=5

x= 10

z=6

y=4

Zhang Hong got six questions right.

Li Chao got four questions right.