Lily got 72+64= 136 (points).

Suppose we get the X question right every day. Let Lili do the Y problem correctly.

20x- 12( 10-x)= 72 20y- 12( 10-y)= 136

32x= 192 32y=256

x=6 y=8

So the solution of the original equation is x=6, so the solution of the original equation is y=8.

Answer: I answer 6 questions correctly every day, and Lili answers 8 questions correctly.

Give more! ! Thank you!