GMAT Sux wrote:Can someone explain the solution on this:

X% of Y% of Z% is decreased by Y%. What is the result?
A) 100XYZ-XY^2Z/1,000,000
B) XZ-Y/100
C) XZ-Y/10,000
D) XYZ-2Y/100
E) XYZ-2Y/10,000

THANKS!!!

The question is a bit ambiguous but I think I have a solution.

X% can be written as X/100, the same follows for Y and Z

We will first find the value of X% of Y% of Z%, which can be rewritten as:

100 [ (X/100) * (Z/100) * (Z/100) ]

I am not certain about the 100 in front of this problem but it is necessary for me to come up with a correct solution. My justification is that the 100 in the beginning represents the "whole value" which the percentage needs to be found from.
For example.
If Z% = Z/100, then to find Z, you would take 100*(Z%) = Z

OK, I know thats a little confusing but bear with me.

Now we simplify the above bold equation into XYZ/10,000

X*Y*Z = XYZ
[ 100*100*100 ] = 1,000,000

100 [ (XYZ) / (1,000,000) ] = (XYZ) / (10,000)


Now, to reduce by Y% we can multiply by (100-Y)/100
So the problem will look like this.

[(XYZ)/(10,000)] * [(100-Y)/(100)]

This equals

{[100XYZ] - [ X*(Y^2)*Z ] } / (1,000,000)



I know this is still confusing, if you have any questions feel free to message me.