2 is incorrect. Weighted average score = σ score * weight = 90 * 20%+82 * 32%+65 * 44%+40% * 4% = 72.856.

3 because the good score is 76~85, 85/40=2...5, 2 people are unqualified.

2/4%*20%/ 10%=50 excellent students and 50 people.