If a rectangular region has perimeter P inches and area A sq

upon further investigation of my own work, this will NOT work!
What I wrote for statement 1 shows that it is possible for it NOT to be a square, but does not show whether it CAN be a square. I need to do a 2-way proof (that is, show that with that equation it CAN be a square and can also NOT be a square). I did half of that. Not good enough because if it is NOT a square, it would still be sufficient since I would be able to answer the question. I need to prove that it does NOT have the potential to become a square, not just proof that it is possible that it is not a square.

For statement one, the work I showed still makes it clear that it can only be a square, since the four parameters would HAVE to be the same for the equation to work.

In statement 2; if all we have proved is x=y , then it could be a rhombus too right? Without knowing if the angles are 90 degrees, how can we be certain?

We are told that the region is a rectangle. So, angles are 90 degrees. A rhombus with 90 degrees angles is a square.
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Hi avigutman - i know this was discussed on quantreasoning.com

While I do understand this problem - i am still un-easy with my steps.

Whenever I feel this, i try to create a 'variation' of the original problem, to get a deeper understanding of the concept

But i am struggling to create a version of this problem

Can you perhaps think of one ? i want to see if i can have truly understood the concept of this problem

If you can't think of a variation, thats totally fine, no worries

Thank you

jabhatta2 Can you articulate what your steps are? That should help you get a deeper understanding of the concept.
And if you mess it up, that'll be a good learning opportunity.

hI avigutman - here is what i did for S1

For S1 - attached is what I did for S1 . Found that the length of the region (represented by 'a' can be zero or can be three.

Now
-- a = zero. That too me doesnt make sense and thus "a"= zero can be dropped as a possible value of 'a'
-- Thus a = three only.

In Yes /No question - S1 should work for every value of "a". S1 only works when a = 3

Thus, Not sufficient.

My question was on S2

avigutman - For S2, here is what I did

I am not sure what Zero = Zero represents (Specifically, how is zero=zero, different from a = zero, which is what i got in S1 and rejected)

I was not getting a value of "A" unlike in S1.

I think i was struggling because from S2 -- i was not getting values of "A"

Thus i wasnt sure what to make from S2 with regards to zero = zero.

jabhatta2


Are you using the question as if it were a statement (assuming the answer to the question is YES, and using that as if it were known?), and then testing what that means for S1?
If so, that's data validation, not data sufficiency.


I'm not sure what you mean. The statements are always truthful. Again, seems like you're using the question to validate the statement.



Why is that not sufficient?

Hi avigutman - Yes, i think i was doing what you mentioned in the yellow

I am taking the question itself as 'TRUE' --> inserting it into the statements --> validating the statement instead [is the statement True or False]

• In the Case of validating S1 = i got True when length is 3 only. In case length was some other length, statement 1 would be FALSE.
• In case of the validating S2 -- I got S2 as True, irrespective of the value of the length of the square

Do you mind discusing my process (regarding what i did) in the next AMA (if you believe this mistake is perhaps usefull for the class to know about) - validating statements. Why is that not a legitimate strategy - uneven results / perhaps an analogy for a question WHERE it wont work ?

Below is a simpler example and the process i followed



I think i thought like this because i followed some version of this process in another quant question

Here is how i had solved S2 in the referenced question and i think i picked up this DS strategy because of this question



I think given i was allowed to do some version of 'going backwards' i thought i could do the same in the original question

Now that we've discussed in the AMA, would you like to try to explain here the errors in your approach and how you'd attack the problem differently now, jabhatta2?

Hi avigutman - last session on quantreasoning.com was very helpful. Here was my mistakes / insights from just this one problem

(a) my mistake was assuming the question as 'True'. Then plugging that information INTO S1 & S2 - That was a mistake. It should be the other way around

(b) The process should be instead
info from statement + free information == Can you proove the question

What i found interesting were the following insights

In fact avigutman --- i can make up a new problem and figure out whether the statement is sufficient



It is this kind of amazing insights that make quant reasoning AMA's unparallel in terms of building logic for prospective students

It is given that it's a rectangular region, so we know it has 90-degree angles

Let's assume the sides of the region as 2 and 2. If any of the equations satisfy we can consider that the rectangular region is a square
Perimeter = 2(2+2) = 8
Area =l*b = 2*2 = 4

1) P=4/3*A
8 = 4/3 * 4
24 is not equal to 16

2) P = 4\sqrt{A}
8 = 4\sqrt{4}
8 = 4*2
8=8
Correct Answer is B

Hi Bunuel, Can you share more of such question types as you have done for various other question types ?

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