Question

If three rectangular holes of 1.5m x 0.3m x 200mm are placed on the wall, a). How many cubic meters of concrete needed to build the wall? b). What is the total volume of the rectangular solid holes? 

Answer 1

Soution. Find the volume of a rectangular hole

$$V_0=1.5\times0.3\times0.2=0.09m^3$$

Therefore the total volume of the rectangular solid holes is equal

$$V=3V_0=3\times0.09=0.27m^3$$

The volume of concrete will be 0.27 m^3 less than when building a wall without holes.

To find the exact value for the volume of concrete in a), I need the parameters of the length, the width and the height of the wall.

Answer. a) The volume of concrete will be 0.27 m^3 less than when building a wall without holes. b)

$$V=0.27m^3$$