Find the number of bricks, each measuring 25 cm, 12.5 cm and 7.5 cm required to construct a wall 6 m long , 5 m high and 50 cm thick, while the cement and sand mixture occupies `1/20 th` of the volume of the wall.

Explanation

Volume of the wall `(V_w) = l**b**h = 6*5*50/100 = 15m^3`

Volume of the cement and the sand mixture `(V_m) = 1/20*15 = 3/4m^3`

So, Volume of the bricks `(V_b) = V_w - V_m = 15-3/4 = 57/4m^3`

Now, volume of a single brick `(V_s) = 25/100**12.5/100**7.5/100 = 3/1280m^3`

So, total number of bricks required `= V_b/V_s = (57/4)/(3/1280) = (57**1280)/(4**3) = 19**320 = 6080`

So, `6080` bricks will be required to make a wall.