Question

7. A lane, 150 m long and 9 m wide, is to be paved with bricks, each measuring 22.5 cm by
7.5 cm. Find the number of bricks required

Answer 1

Given

• Dimensions of a lane :-
• Length of a lane = 150 m
• Breadth of a lane = 9 m

• Dimensions of a brick :-
• Length of a brick = 22.5 cm
• Breadth of the brick = 7.5 cm

To find

• Number of bricks required to build a lane.

Solution

To find the number of brick, we will find the area of the lane and the area of the brick.

[Note. Their units should be same. As we are given the dimensions of the brick in cm, we will convert it into m.]

Then to find the number of bricks - Divide the area of lane by area of bricks.

Let's do :-

Using formula,

❖ Area of lane = l × b

where,

• l = length of the lane
• b = breadth of the lane

Substituting the given values,

⟼ 150 × 9

⟼ 1350 m²

★ Area of lane = 1350 m²

Using formula,

Area of bricks = l × b

Substituting the given values,

⟼ 22.5 × 7.5

⟼ 168.75 cm²

As we know that,

⟼ 1 cm = 0.01 m

To convert the value from cm to m divide the value by 100 m.

⟼ 168.75/(100 × 100)

⟼ 0.016875 m²

★ Area of bricks = 0.016875 m²

Number of bricks required to build the lane = Area of lane/Area of bricks.

⟼ 1350/0.016875

⟼ 80,000

❖ Number of bricks required = 80,000.

Answer 2

Given Question:-

• A lane, 150 m long and 9 m wide, is to be paved with bricks, each measuring 22.5 cm by 7.5 cm. Find the number of bricks required.

─━─━─━─━─━─━─━─━─━─━─━─━─

Answer

─━─━─━─━─━─━─━─━─━─━─━

To Find :-

• Number of bricks required.

─━─━─━─━─━─━─━─━─━─━─━─━─

Concept used :-

$1. \: \boxed{ \red{ \tt \: Area\:of\:Rectangle=Length × Breadth}}$

─━─━─━─━─━─━─━─━─━─━─━─━─

Given :-

Dimensions of brick :-

• Length of brick = 22.5 cm
• Breadth of brick = 7.5 cm

Dimensions of Lane :-

• Length of Lane = 150 m = 150 × 100 = 15000 cm
• Breadth of Lane = 9 m = 9 × 100 = 900 cm

$\begin{gathered}\bf\red{Now,}\end{gathered}$

$\green{ \tt \: Area_{(brick)} = Length \times Breadth}$

$\bf\implies \:Area_{(brick)} \: = \: 22.5 \times 7.5 \: {cm}^{2}$

$\begin{gathered}\bf\blue{Now,}\end{gathered}$

$\purple{ \bf \: Area_{(lane)} = Length \times Breadth}$

$\bf\implies \:Area_{(lane)} = 15000 \times 900 \: {cm}^{2}$

$\begin{gathered}\bf\green{Now,}\end{gathered}$

$\red{ \bf \: No. \: of \: bricks \: required} \: = \tt \: \dfrac{Area_{(lane)}}{Area_{(brick)}}$

$\tt \: = \dfrac{15000 \times 900}{22.5 \times 7.5}$

$\tt \: = \dfrac{15000 \times 900 \times 10 \times 10}{225 \times 75}$

$\tt \: = 80000$

$\bf\implies \boxed{ \blue{ \bf \: \:No. \: of \: bricks \: required  = \: 80000</p><p>}}$