Question

find the number of bricks each measuring 25*12.5*7.5cm required to construct a wall 6cm long 5m heigh and 0.5 thick while the cement and sand mixture occupies 1/20th of the volume of the wall

Answer 1

Volume of wall = Length × breadth × height = 6m × 5m × 0.5 m = 15 m³
According to question, sand mixture occupies the wall's volume of 1/20th
so, volume for bricks = volume of wall - volume of sand
= 15 - 15/20 = 15 × 19/20 = 57/4 m³ = 14.25 m³

Now, volume of each brick = 25 cm × 12.5cm × 7.5 cm = 2343.75 cm³
volume of each brick = 2.34375 × 10⁻³ m³

Now, number of bricks = volume occupies all bricks /volume of each brick
= 14.25/2.34375 × 10⁻³ = 6080

Hence, answer should be 6080