Re: A cube of cheese is 3-inches high. The cheese is sliced twic
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09 Apr 2018, 14:34
Let me try this one out - If the cube is sliced twice it will result in 3 cuboids -
Scenario 1: The cheese is sliced twice along length at 1 inches, the 3 cuboids formed will have length (l) = 1 inch, width(w) = 3 inches, height(h) = 3inches.
The area of surface Area of one of these cuboids = 2*(w*h) + 2*(h*l) + 2*(w*l) = 2*(3*3) + 2*(3*1) + 2*(3*1) = 30
Surface area of all 3 cuboids = 3 * 30 = 90
Scenario 2: The cheese is sliced first along length at 1.5 inches giving 2 equal cuboids now cut one of cuboids from width giving 2 more cuboids w = 1.5 inch, h = 3inches, l = 1.5 inch. In total 3 cuboids formed.
First cuboid will have length (l) =2 inch, width(w) = 3 inches, height(h) = 3inches. Second and Third Cuboid cuboid will have length (l) =0.5 inch, width(w) = 3 inches, height(h) = 3inches.
The area of surface Area of First cuboid = 2*(w*h) + 2*(h*l) + 2*(w*l) = 2*(3*3) + 2*(3*1.5) + 2*(3*1.5) = 26 inches
Surface area of second and third cuboids = 2*(1.5*3) + 2*(3*1.5) + 2*(1.5*1.5) = 22.5 inches
Total Surface Area of 3 cuboids 26 + 2*(22.5) = 71inches
Hence Answer D
However, this took a bit of time in trying out different scenarios.