Asmakan wrote:
If \(a^x=b^y=c^z\), \(\frac{b}{a}=\frac{c}{b}\), and a, b and c have different values.
Quantity A |
Quantity B |
\(\frac{2z}{x+z}\) |
\(\frac{y}{x}\) |
A)Quantity A is greater.
B)Quantity B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.
ID: Q02-86
Let's build on Chakolate's solution....
If \(a^x=b^y=c^z\), \(\frac{b}{a}=\frac{c}{b}\), then it COULD be the case that a=2, b=4, c=8, x=3, y=3/2, z=1.
In this case, we get:
QUANTITY A: 2z/(x+z) = (2)(1)(3 + 1) = 2/4 = 1/2
QUANTITY B: y/x = (3/2)/3 = 1/2
It COULD be the case that a=2, b=4, c=8, x=0, y=0, z=0.
In this case, we get:
QUANTITY A: 2z/(x+z) = 0/0
QUANTITY B: y/x = 0/0
Can we say that 0/0 = 0/0?
No.
0/0 is undefined. In other words, it's not an actual number.
It's like asking "Which is greater, lemon or lemon?"
Since we can only compare numbers in a Quantitative Comparison question, this is a faulty question.
If this were an official GRE question, there would be some proviso that says the denominator cannot be zero.
Cheers,
Brent
_________________
Brent Hanneson – Creator of greenlighttestprep.com
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