A building is in the form of a cylinder surmounted by a hemispherical done on the diameter of the cy...........

Quantitative Aptitude (CDS) Mensuration 3D

A building is in the form of a cylinder surmounted by a hemispherical done on the diameter of the cylinder. The height of the building is three times the radius of the base of the cylinder. The building contains $67\frac{1}{21} \;m^{3}$ of air. What is the height of the building?