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From statement 1, we know that the tens digit of K+9 is 3. However, we're also told that the last digit of k is non-zero. So the last digit cannot be 1.

If the units digit is from 2-9, if we add 9, we will have a carry over of 1 to the tens digit position. In order to get 3 in the tens position, the original number must be holding a 2 in the tens position.

Statement 1 is therefore sufficient.

From statement 2, we know the tens digit of K+4 is 2. However, we're also told the last digit of k is non-zero, so the last digit cannot be 6. It can be 1-5, 7-9. If the units digit is 1-5, the tens digit is 2. If the units digit is 7-9, the units digit is 1. Since we have two possible solutions, Statement 2 is not sufficient.

Thanks for the expln. guys. ywilfred, your reasoning makes it very easy to understand.
Well the OA is strangely A. Strangely coz vivek makes a valid point!! _________________

I would have chosen A as well because I did not think about the possibility of k being negative. How do you prevent yourself from overanalyzing a question like this? The negative case is a valid point...

Thanks for the expln. guys. ywilfred, your reasoning makes it very easy to understand. Well the OA is strangely A. Strangely coz vivek makes a valid point!!

Just out of curiosity, what is the source of this question? I doubt the OG would allow you to second guess the nature of the question (in this case, we're left wondering if the 3 digit number could be negative)

I got it as A too! So, being wrong sometimes has its advantages too... or am I wrong?

A is the OA given for this question. The only question was whether the 3 digit number can be negative, that's all. But I suppose ETS or Pearson will set questions that does not leave you in any doubt.

I would have chosen A as well because I did not think about the possibility of k being negative. How do you prevent yourself from overanalyzing a question like this? The negative case is a valid point...

I have exactly same question as you. I hope real test will not have questions with open scope.

ywilfred has a point.
So far, I have not seen any question by ETS (in OG or any other source) having any doubtful answer but at the same time I have seen couple of controversial questions in other non-ETS material. I think we should be careful, not to take our mistakes too seriously in such a material, just learn & move ahead...

Just wanted to put one of my learnings...
Whenever there is a DS question, which just says "a number",

Don't forget to check,

1) Can it be an integer
2) Can it be a floating ppoint number (or a fraction)
3) Can it be a zero (sometimes I made mistakes by ignoring it to be a zero)

& in each of 1) & 2) above,

a) can it be a negative (integer/float)
b) can it be a positive (integer/float)

Just wanted to put one of my learnings... Whenever there is a DS question, which just says "a number",

Don't forget to check,

1) Can it be an integer 2) Can it be a floating ppoint number (or a fraction) 3) Can it be a zero (sometimes I made mistakes by ignoring it to be a zero)

& in each of 1) & 2) above,

a) can it be a negative (integer/float) b) can it be a positive (integer/float)

Good roundup, Vivek.... and floating point number.. hmm.. computer engineering?

I couldn’t help myself but stay impressed. young leader who can now basically speak Chinese and handle things alone (I’m Korean Canadian by the way, so...