Question

Calculate the number of bricks, each measuring 25 cm x 15 cm x 8 cm required to construct a wall of dimensions 10 m x 4 cm x 6 m when 10% of its volume is occupied by mortar-
A. 720
B. 600
C. 660
D. 6000

Answer 1

Hint- To solve this question, first we need to calculate the total volume of the wall and volume of the wall occupied by the bricks and then we also calculate the volume of each brick. And in the final step we divide the volume of each wall by the volume of each brick. So, we get a number of bricks required.

Complete step-by-step answer:
Given wall dimensions as: 10 m long, 0.04 m high and 6 m thick.
⟹ volume of wall =10×0.04×6=2.40 ${m^3}$
Given, cement and sand mixture occupies 10% of the volume of the wall.
Therefore, volume of the wall occupied by the bricks = (1−$\dfrac{1}{{10}}$) volume of wall = $\dfrac{9}{{10}}$ volume of the wall
= $\dfrac{9}{{10}}$×2.40= 2.16 ${m^3}$
Now, volume of each brick = $\dfrac{{25}}{{100}}$m$ \times $$\dfrac{{15}}{{100}}$m $ \times $$\dfrac{8}{{100}}$m
So, the number of bricks required = $\dfrac{{{\text{volume of each wall}}}}{{{\text{volume of each brick}}}}$
                                                             = $\dfrac{{2.16}}{{\dfrac{{25}}{{100}} \times \dfrac{{15}}{{100}} \times \dfrac{8}{{100}}}}$= 720
Hence, 720 bricks of given dimensions are required to construct the wall.
Thus, option (A) is the correct answer.

Note- As we know bricks and walls are mostly rectangle in nature. Therefore, we use all rectangular formula (like volume and area) for calculating the volume of bricks i.e.
                                           volume of bricks = ${{length \times breadth \times height}}$