Answer:
9 bought in advance
3 did not buy in advance
Explanation:
Number of people in line = 60
The total number of people surveyed :
Every 5th person in line is questioned starting with the first in line :
Number of people sampled:
1, 6, 11, 16, 21, 26, 31, 36, 41, 46, 51, 56
Total sampled from the 60 people in line = 12
If 9 people said yes ;
Then ;
9 people bought tickets in advance and ;
12 - 9 = 3 did not