Question

Find the number of bricks each measuring 2.5cm x 12.5cm x 7.5cm required to cunstruct a wall

Answer 1

Your question is incomplete

I think u missed out the volume of wall or measurement of wall

Only then we can calculate by finding the volume of wall and bricks

divide the volume of wall by volume of bricks..u will get the number

Answer 2

Question :

Find the number of bricks, each measuring 25cm

× 12.5cm × 7.5cm required to construct a wall 6 m long, 5m high and 0.5m thick, while the cement and sand mixture occupies 1/20 of the volume of the wall.

Answer:

We have,

Volume of the wall = (6×5×0.5)m³ = 15 m³

Volume occupied by the mortar

= $\sf\frac{1}{20}×Volume\:of\:the\:wall$

$\sf\frac{1}{20}×15\:m^3$

$\sf{0.75\:m^3}$

•°• $\sf\qquad{Volume\:occupied\:by\:bricks=(15-0.75)m^3=14.25\:m^3}$

$\sf\qquad{Volume\:of\:each\:brick=}$$\sf\frac{25}{100}×$$\sf\frac{12.5}{100}×$$\sf\frac{7.5}{100}m^3$

$\leadsto$$\sf\qquad\frac{3}{1280}m^3$

So, required number of bricks =

$\sf\frac{Volume\:occupied\:by\:bricks}{Volume\:of\:each\:brick}$

$\leadsto$ $\sf\frac{14.25}{3/1280}$

$\leadsto$ $\sf{14.25×}$$\sf\frac{1280}{3}$

$\leadsto$ $\sf\frac{1425}{100}×$$\sf\frac{1280}{3}=6080$