if x and ya re positive integers, Advanced Quant guide doubt

by **archit_anand143** Sat Jan 05, 2013 2:41 pm

If x and Y are positive integers, What is the remainder when x^ y is divided by 10?

1. X = 26
2. Y^X = 1

Answer to this question is given as A
I think it should be D as we cannot plug zero here because Zero is neither positive nor negative.
But In explanation in the book Advanced Quant guide values of X and y are assumed to be zero and than statement is proved insufficient.

PLs help me, If I am wrong than pls correct me.......

Regards
Archit

by **jnelson0612** Sat Jan 05, 2013 3:40 pm

archit_anand143 Wrote:If x and Y are positive integers, What is the remainder when x^ y is divided by 10?

1. X = 26
2. Y^X = 1

Answer to this question is given as A
I think it should be D as we cannot plug zero here because Zero is neither positive nor negative.
But In explanation in the book Advanced Quant guide values of X and y are assumed to be zero and than statement is proved insufficient.

PLs help me, If I am wrong than pls correct me.......

Regards
Archit

Hi Archit,
Can you direct me to a page number for this problem? Because if the author suggests either X or Y could be 0 I will contact headquarters and inform them of this error.

HOWEVER, we still can't rule out statement 2 with some simple number testing. Let's remind ourselves of the question stem and statement:

If x and Y are positive integers, What is the remainder when x^ y is divided by 10?

2. Y^X = 1

Test case #1:
Y=1
X=1
These numbers both fit the statement. Let's use them to answer the question. 1^1 divided by 10 has a remainder of 1

Test case #2:
Y=1
X=2
What is the remainder when 2^1 is divided by 10? The remainder is 2.

I've just shown that I can use two different sets of numbers (that both fit the statement) and get two different answers to the question. I have proven that this statement is insufficient.

by **archit_anand143** Sun Jan 06, 2013 12:27 am

Hi Jamie,

Thanks for your prompt reply

Sorry for creating a confusion here, in the solution it is mentioned zero to make it clear that it cannot be a possible solution.....But it is very confusing, when reading fast, I observed the intent after close reading
By the way it son page no 286.....

srry again for confusion..

Regards

Archit

by **tim** Sun Jan 06, 2013 7:52 pm

no problem. i hope Jamie's explanation for why 2 is insufficient helped..

if x and ya re positive integers, Advanced Quant guide doubt

if x and ya re positive integers, Advanced Quant guide doubt

Re: if x and ya re positive integers, Advanced Quant guide doubt

Re: if x and ya re positive integers, Advanced Quant guide doubt

Re: if x and ya re positive integers, Advanced Quant guide doubt