GMAT practice question

[shamrocked]

I don't understand how to work this problem. Any assistance would be a great help!

If X = (a/2) + (b/2 to the 3rd) + (c/2 to the 4th), where a, b, and c are each equal to 0 or 1, then x could be each of the following EXCEPT

A. 1/16
B. 3/16
C. 5/16 (answer)
D. 10/16
E. 11/16

Thanks!

 

[Deleted member 4993]

I don't understand how to work this problem. Any assistance would be a great help!

If X = (a/2) + (b/2 to the 3rd) + (c/2 to the 4th), where a, b, and c are each equal to 0 or 1, then x could be each of the following EXCEPT

A. 1/16
B. 3/16
C. 5/16 (answer)
D. 10/16
E. 11/16

Thanks!

X = (a/2) + (b/2)[sup:3shp6oum]3[/sup:3shp6oum] + (c/2)[sup:3shp6oum]4[/sup:3shp6oum] = a/2 + b[sup:3shp6oum]3[/sup:3shp6oum]/8 + c[sup:3shp6oum]4[/sup:3shp6oum]/16 = 1/16 * (8a + 2b + c)

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