An open rectangular box is made of wood 2cm thick. If the internal dimensions of the box are 50cm long, 36cm wide and 20cm deep, the box volume of wood in the box is

A.
11 520cm^{3} 
B.
36 000cm^{3} 
C.
38 200cm^{3} 
D.
47 520cm^{3}
Correct Answer: Option A
Explanation
Internal dimension are 50cm, 36cm and 20cm
internal volume = 50 x 36 x 20cm^{3}
1000 x 36cm^{3}
= 36000cm^{3}
External dimension are 54cm x 40cm x 22cm
= 2160cm^{2} x 22cm = 47520cm^{3}
Volume of wood = Ext. volume – Int. volume
= 47,520cm^{3} – 36,000cm^{3}
= 11,520cm^{3}