∴ Let the frequency of the first upper group be 6a, then the frequencies of other upper groups are na, 00a, 4a, 2a in turn.
The frequency of the fifth upper group is 40,
∴2a=40，
∴a=20，
The number of students selected in this survey is 6a+na+00a+4a+2a=600 (persons).
A: The number of students selected in this survey is 600.
(2) According to (0), there are 480 qualified people and 020 excellent people.
∴ Their respective percentages are 480 600× 000% = 80% 020 600× 000% = 20% (0 point).
A: The passing rate and excellent rate are 80% and 20% respectively.
(z) According to (2), the number of qualified people is 8000×80%=6400 (people),
The number of outstanding people is 8000×20%=0600 (people).
A: Of the 8,000 students, about 6,400 passed and about 0,600 were excellent.