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Ken baked, frosted, and decorated a rectangular cake for the last Math Club meet

ID: 3186077 • Letter: K

Question

Ken baked, frosted, and decorated a rectangular cake for the last Math Club meeting. The cake was 3 inches high, 12 inches wide, and 16 inches long. He centered the cake on a piece of cardboard whose rectangular top surface had been covered with aluminum foil, as shown in the figure below. 12" 16 14 3" 12 C10 35. Ken used a piece of cardboard large enough to allow the cardboard to extend 2 inches beyond the cake on all sides. What is the area, in square inches, of the aluminum foil that is exposed on the top surtace of the cardboard? A. 60 18 B. 64 8812

Explanation / Answer

35. As the card board extends by 2 inches on all sides of the cake, so, the length and width of the exposed surface of the cardboard will increase each by (2+2)=4 inches.

Thus length of top cardboard surface = (16+4) inch

= 20 inch

And width of top surface = (12+4) = 16 inch

Hence, area of the top cardboard surface = l × w

= (20 × 16) sq. inch

= 320 square inch

Area of the bottom surface of cake = (16×12) sq. inch

= 192 sq. inch

Hence, required exposed area of the aluminium foil

= (320-192) = 128 square inch. Option E.