Test center of Class A: Analysis: The number of people in Class A from 80 to 90 can be found from the histogram, the number of people in Class B in this range can be found from the fan chart, and the number of people in Class C can be found from the frequency statistics table. So you can get the total number of people. Class A: 60-3-7- 12- 18=20 (human) Class B: 60× (1-35%-10%-5%-20%) = 65438.