Question

The area of the 4 walls of a room is 168 m². The breadth and height of the room are 10 m and 4 m respectively. Find the length of the room.

Answer 1

Let the length of the room be l m.
Given:
Breadth of the room = 10 m
Height of the room = 4 m
Area of the four walls = [2(l + b)h] sq units.
= 168 m²
∴ 168 = [2(l + 10) $\times$ 4]
⇒ 168 = [8l + 80]
⇒ 168 - 80 = 8l
⇒ 88 = 8l
⇒ l = $\left(\frac{88}{8}\right)$ m = 11 m
∴ Length of the room = 11 m