If you choose 1 and fill in the blanks with 3, then the fill-in-the-blank score is 9*3+2*4=35, and the total score is 35+48=83, which is definitely unqualified.

If you choose two blanks, the score of choosing blanks is 8*3+3*4=36, and the total score is 36+48=84.

If you choose three and fill in the blanks with 1, then the score of the fill-in-the-blank question is 7*3+4*4=37, and the total score is 37+48=85. That's right.

So three wrong choices, that is, seven right ones.