GRE Tough Quant Question - Any help would be appreciated!!!!

[grehelpme]

Hi, Can someone please help me solve this using numbers.

 

For all numbers K, k* = 1/k

 

Quantity A

((K + 2)*)*

 

Quantity B

(1/K+2)*

 

 

 

The correct Answer is C. I'm confused as to what the question is saying. I tried to solve it by plugging in 2 for K.

For all numbers 2, 2* = 1/2

 

Quantity A:

((2+2)*)* = ((4)*)* = 4 * 1/2 = 2 * 1/2 = 1 Can someone please advise me with what I'm doing wrong.

[grenyc999]

Hi grehelpme,

 

GRE loves to ask these types of questions and the good news is these are very difficult to solve.

 

For this problem, k* = 1/k.

 

so, (K+2)* = 1/(K+2)

.

=> ((K+2)*)* = (1/(K+2))* which is same as quantity B.

 

If you want to solve it using an example, Let's say K=2, then

 

Quantity A: ((2+2)*)* = ((4)*)* = (1/4)* = 4

Quantity B: (1/2+2)* = (1/4)* = 4

[rajghosh95]

Hi, Can someone please help me solve this using numbers.

 

For all numbers K, k* = 1/k

 

Quantity A

((K + 2)*)*

 

Quantity B

(1/K+2)*

 

 

 

The correct Answer is C. I'm confused as to what the question is saying. I tried to solve it by plugging in 2 for K.

For all numbers 2, 2* = 1/2

 

Quantity A:

((2+2)*)* = ((4)*)* = 4 * 1/2 = 2 * 1/2 = 1 Can someone please advise me with what I'm doing wrong.

 

 

 

 

The question is very simple...any number k* will be equal to its reciprocal. Just plug in various values for k. First try 2, then 0, then a negative number.... The answer will be C in every case... Thank u :)

[Corey]

Yeah, I think the key to this question is rewriting Quantity A, because ((k+2)*)* = (1/(k+2))*. That way, you can see that the two quantities are equal.