Question

Length of a rectangle is 4 m less than 3 times its breadth. If the perimeter of rectangle is 32 m. Then find its length and breadth.

Answer 1

Let breadth of a rectangle (b) = a m 

Length of rectangle (l) = 4 m less than 3 times of breadth 

= (3 ∙ a – 4) m 

Given perimeter = 2(l + b) = 32 m 

⇒ 2[3a – 4 + a] = 32

⇒ 2[4a – 4] = 32 

⇒ (8a – 8) = 32 (Distributive property) 

⇒ 8a – 8 + 8 = 32 + 8 (Add 8 on both sides) 

⇒ 8a = 40

⇒ 8a/8 = 40/8 (Divide by 8 on both sides)

⇒ a = 5 

∴ breadth (b) = 5 m 

length (l) = 3a – 4 

= 3(5) – 4 = 15 – 4 = 11 m 

∴ length = 11 m and breadth = 5 m.