11. A student did a survey of teachers' ages
The cumulative frequency curves show information about the ages of the male teachers and
the ages of the female teachers.
100
90
80
70
60
Cumulative
Frequency 50
male teachers
40
30
female teachers
20
10
0
20
30
40
50
60
70
Age in years
(a) Find an estimate for the number of the male teachers older than 50 years of age.