Option 2 : 110%

**Given:**

Height of a boy and a girl in a class is in the ratio of 2 ∶ 3 and the number of girls and boys are in the ratio of 7 ∶ 5.

**Concepts used:**

Total height of boys = Height of 1 boy × number of boys

Total height of boys = Height of 1 boy × number of boys

Percentage by which height of girls is more/less than the height of boys = {(Height of girls – height of boys)/Height of boys} × 100

**Calculation:**

Height of a boy and a girl in a class is in the ratio of 2 ∶ 3.

⇒ Height of a boy = 2x

⇒ Height of a girl = 3x

The number of girls and boys are in the ratio of 7 ∶ 5.

⇒ Number of boys = 5y

⇒ Number of girls = 7y

⇒ Total height of boys = 2x × 5y = 10xy

⇒ Total height of girls = 3x × 7y = 21xy

Percentage by which height of girls is more/less than the height of boys = {(Height of girls – height of boys)/Height of boys} × 100

⇒ Percentage by which height of girls is more/less than height of boys = {(21xy – 10xy)/10xy} × 100 = 110%

**∴**** The height of girls is more than the height of boys by 110%.**