A cylindrical motor of height 12cm has uniform thickness of 2cm. If the diameter of its outer cross section is 10cm, Find the volume of the constituent material. (take (pi) = (frac{22}{7})

A.
(frac{6600}{7})cm^{3} 
B.
270cm^{3} 
C.
660cm^{3} 
D.
(frac{4224}{7})cm^{3} 
E.
(frac{1980}{7})cm^{3}
Correct Answer: Option D
Explanation
V = (pi)r^{2}h
= (frac{22}{7}) x 5^{2} x 12 – (frac{22}{7}) x 3^{2} x 12
= (frac{22}{7}) x 12(5^{2} – 3^{2})
= (frac{4224}{7})