PASCAL 2010 Problem 16

Four identical squares are cut from the corners of the rectangular sheet of cardboard shown. This sheet is then folded along the dotted lines and taped to make a box with an open top. The base of the box measures 5\:cm by 4\:cm. The volume of the box is 60\:cm^3. What was the area of the original sheet of cardboard?

Answer Choices
A. 56\:cm^2
B. 110\:cm^2
C. 156\:cm^2
D. 180\:cm^2
E. 210\:cm^2

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