Question

If three rectangular holes of 1.5m x 0.3m x 200mm are placed on the wall,

9. How many cubic meters of concrete needed to build the wall?

10. What is the total volume of the rectangular solid holes?

Answer 1

9)

Total volume of concrete needed to build the wall = actual volume of the wall - volume of the three holes

10)

Total volume of rectangular solid holes =$3\times volume \ of \ one \ hole =3\times1.5\times0.3\times0.02=0.27m^3$