What is the surface area of a certain rectangle solid?

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What is the surface area of a certain rectangle solid?

1) The volume of the solid is 96
2) The one face's area of the solid is 12


* A solution will be posted in two days.
Source: — Data Sufficiency |

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by GMATinsight » Mon Mar 07, 2016 4:30 am
What is the surface area of a certain rectangle solid?

1) The volume of the solid is 96
2) The one face's area of the solid is 12


To know the Surface Area of rectangular solid we need the dimensions of the solid
Question : Surface Area of Solid = ?

Statement 1: The volume of the solid is 96
i.e. L*B*H = 96
we nee to calculate 2(LB+BH+LH) but the individual products of two sides at a time are missing hence
NOT SUFFICIENT

Statement 2: The one face's area of the solid is 12
Other sides are missing hence
NOT SUFFICIENT

Combining the two statements
L*B*H = 96 and AREA of one face = 12
let BH= 12
i.e. L = 96/12 = 8
but BH = 12 may give us either B=2 H= 6 or B=3 H=4 giving us different values and hence different values of Area. Hence
NOT SUFFICIENT

Answer: Option E
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by DavidG@VeritasPrep » Mon Mar 07, 2016 7:09 am
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by Max@Math Revolution » Mon Mar 07, 2016 3:41 pm
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

What is the surface area of a certain rectangle solid?

1) The volume of the solid is 96
2) The one face's area of the solid is 12


There are 3 variables(length, width, height) for a rectangular solid, which should match with the number of equations. So you need 3 equations. For 1) 1 equation, for 2) 1 equation, which makes E the answer.