Passage:

The adjoining Histogram shows frequency distribution of ages of 20 teachers in a school. Based on Historgram choose correct option for question no 70-72.

How many the numbers of teachers of age group 40-50 is more than the number of teachers of age group '20-30' is

4

No. of teachers in age group 40-50 = 7

No. of teachers in age group 20-30 = 3

Difference = 7 - 3 = 4