What is the value of integer n?

Question

(1) n = n^4
(2) 1^n ≠ n

I came across a question in Kaplan's 2014 review book. I am not too satisfied with the answer and explanation given. Please help me around here.

Answer in Kaplan

They explained saying B is right with the implication that the value of n = 0 will fit perfectly and no other possibility.

But I am confused and I think -1 will also be a valid candidate for the equation, making it an E-er.

What do you think?

Also, the Kaplan review problems seem to be fairly less complex. Does this reflect real GMAT? 
P.S: I haven't taken any Kaplan CATs yet.

Thanks,
Yuvi

gmatprav · Answer

B is clearly incorrect.

Stmt 2: 1^n != n.

if n=0 then 1^0 != 0 
if n=2 then 1^2 != 2
if n=3 then 1^3 != 3 and so on hence n can ANY integer other than 1 & -1. Multiple values of n are possible. not sufficient.

Stmt 1: n = n^4

n can be 0 or 1. not sufficient.

(1)+(2) n can be only 0.   hence C must be the answer.

On the other hand if statement 2 says 1^n = n. then n can only be 1 or -1. Again here also C will be the solution.

MacFauz · Answer

1^-1 is equal to 1 which is not equal to -1. But only 0 satisfies both statements.
Answer should be C

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stne · Answer

Seems answer should be C

Statement 2 says =  1^n 
eq n 
so n can be any integer other than 1 and -1 
statement 2 is valid for n= 2,3,4 etc 
So multiple values of n insufficient

1+2 
n= 0 only 
answer C

May moderator kindly change the OA or provide explanation if answer is indeed b
Thank you

(My 200th mile stone)

Bunuel · Answer

Done.

What is the value of integer n?

(1) n = n^4 --> n = 0 or n= 1. Not sufficient.

(2) 1^n ≠ n --> the integer powers of one are 1, thus 1^n = 1, so we are given that 1 ≠ n. Not sufficient.

(1)+(2) Since n ≠ 1, then n = 0. Sufficient.

Answer: C.

stne · Answer

erred on -1

-1 is a possibility for statement 2 as  1^{(-1)} = 1  and  1
eq -1

chetan2u · Answer

Hello,
(1) n = n^4 
we can rewrite the statement 1 as n^4-n=0..
or n^3(n-1)=0...
so n can be 0 or 1... insuff

(2) 1^n ≠ n..
n can be any value except 1.... insuff

combined it gives the value as 0... SUFF
Ans C

hatemnag · Answer

Hi Chetan2u
i got it right in 1.45 minutes but just by looking and thinking conceptually. 
My question is : Is it dangerous to just look and think without analyzing the expression like what you did above ?
I thought one case of two n = o or 1 
Both statements confirmed my thought and clicked C.

chetan2u · Answer

Hi,
At times we may require to use the method, which you have used , when you are not finding a way to move ahead or you are short of time and you HAVE to answer, but it is equally likely that you miss out on some concepts... and many times you find that C trap..
C trap is when you look and analyze and they give you info which seems perfectly fine to fit in and answer...
 say there are two variables x and y.. I and II give you two equations and you think -two variables and two equations-- solvable so C 
But when you simplify ONE of these two, you realize both are identical..

Now here you can easily anlyze the equation..
and if time is permitting and you know how to move ahead, ANALYZE..

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What is the value of integer n?

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