This question was previously asked in

Territorial Army Paper I : Official Practice Test Paper - 1

Option 1 : 8 m.

**Given**

The breadth of a rectangular hall is three fourth of its length. If the area of the floor is 768 sq. m.

**Concept used**

Area of rectangle = Length × Breadth

**Calculation**

The breadth of a rectangular hall is three fourth of its length.

Length = 3/4 × Breadth

Length = 3x

Breadth = 4x

Area = Length × Breadth

12x^{2} = 768

x^{2} = 64

x = 8m

Length = 24 m and Breadth = 32 m

Difference of Length and breadth

⇒ 32 - 24 = 8 m