Since the maximum number of states ‘10’ lies in the class interval 30-35, this is the modal class.

Lower boundary of the modal class, l = 30

Frequency of the modal class, f_{1} = 10

Frequency of the class preceding the modal class = f_{0} = 9

Frequency of the class succeeding the modal class = f_{2} = 3

Height of the class, h = 5

a = assumed mean = 32.5; h = height of the class = 5

∴ x = 32.5 – \(\frac{23}{35
}\) × 5

= 32.5 – 3.28

= 29.22

Mean = 30.625

Mode = 29.22

**Mode states have a students – teacher ratio 29.22 and on an average this ratio is 30.625.**