Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

If p is the perimeter of rectangle Q, what is the value of p? 1) Each diagonal of rectangle Q has length 10.

2) The area of rectangle Q is 48

I am not able to understand how do you solve a quadratic eqn of this size and conclude that length and breadth can have 2 distinct values. Please help!

Question: \(P=2(a+b)=?\)

(1) \(d^2=a^2+b^2=100\). Not sufficient. (2) \(ab=48\). Not sufficient.

(1)+(2) Square P --> \(P^2=4(a^2+b^2+2ab)\), now as from (1) \(a^2+b^2=100\) and from (2) \(ab=48\) then \(P^2=4(a^2+b^2+2ab)=4(100+2*48)=4*196\) --> \(P=\sqrt{4*196}=28\). Sufficient.

Answer: C.

So you can see that it's not necessary to solve quadratic equation for a and b to get P.

1) Length of diagonal = 10 Length of a diagonal = sqrt{l^2 + b^2} = 10 Squaring both sides, we get (l^2 + b^2) = 100 This is not sufficient since we have one equation and 2 variables.

2) Area = l*b = 48 This is not sufficient since we have one equation and 2 variables.

(l+b)^2 = l^2 + b^2 + 2*l*b Substituting the values obtained in 1) and 2), we can get the value of (l+b) and thus we can calculate the perimeter.

in the book "GMAT review 12th edt.", there is diagnostic test question #48 (DS). ----- If p is the perimeter of rectangle Q, what is the value of p? 1) Each diagonal of rectangle Q has length of 10. 2) The area of rectangle Q is 48. ---- Now, the answer explanation says C is correct. However, when looking at answer 1), I know the hypotenuse of both triangles is 10. Using the Pythagorean theorem, I know that my sides are 8 and 6 -> (5:4:3) x 2.

So p = 2l + 2w = 16 + 12... hence A is sufficient to determine the value.

in the book "GMAT review 12th edt.", there is diagnostic test question #48 (DS). ----- If p is the perimeter of rectangle Q, what is the value of p? 1) Each diagonal of rectangle Q has length of 10. 2) The area of rectangle Q is 48. ---- Now, the answer explanation says C is correct. However, when looking at answer 1), I know the hypotenuse of both triangles is 10. Using the Pythagorean theorem, I know that my sides are 8 and 6 -> (5:4:3) x 2.

So p = 2l + 2w = 16 + 12... hence A is sufficient to determine the value.

You assume with no ground for it that the lengths of the sides are integers. Knowing that hypotenuse equals to 10 DOES NOT mean that the sides of the right triangle necessarily must be in the ratio of Pythagorean triple - 6:8:10. Or in other words: if \(a^2+b^2=10^2\) DOES NOT mean that \(a=6\) and \(b=8\), certainly this is one of the possibilities but definitely not the only one. In fact \(a^2+b^2=10^2\) has infinitely many solutions for \(a\) and \(b\) and only one of them is \(a=6\) and \(b=8\).

For example: \(a=1\) and \(b=\sqrt{99}\) or \(a=2\) and \(b=\sqrt{96}\) or \(a=4\) and \(b=\sqrt{84}\) ...

So knowing that the diagonal of a rectangle (hypotenuse) equals to one of the Pythagorean triple hypotenuse value is not sufficient to calculate the sides of this rectangle.

Hi.. am a member for some while now, however this is my 1st ever post. In Q 48 (data sufficiency) of diagnostic test of OG-12, the diagonal length of rectangle is given as 10 inches, and we need to find the perimeter. According to me, the statement is sufficient in that the sides have to be 6 and 8 inhes (using the pythagorean triple 6-8-10). However, book says it's not sufficient.

Re: Official Guide - 12 - Question D48 [#permalink]

Show Tags

17 Sep 2011, 01:05

deephoenix wrote:

Hi.. am a member for some while now, however this is my 1st ever post. In Q 48 (data sufficiency) of diagnostic test of OG-12, the diagonal length of rectangle is given as 10 inches, and we need to find the perimeter. According to me, the statement is sufficient in that the sides have to be 6 and 8 inhes (using the pythagorean triple 6-8-10). However, book says it's not sufficient.

Can someone plz clarify or explain? Tx

OG is right. You cannot take 6-8-10 to solve this quesion. In the above posts Bunnel and fluke have explained the solution of this question using the right approach. Please refer their posts and reply back if you have any doubts.

There’s something in Pacific North West that you cannot find anywhere else. The atmosphere and scenic nature are next to none, with mountains on one side and ocean on...

This month I got selected by Stanford GSB to be included in “Best & Brightest, Class of 2017” by Poets & Quants. Besides feeling honored for being part of...

Joe Navarro is an ex FBI agent who was a founding member of the FBI’s Behavioural Analysis Program. He was a body language expert who he used his ability to successfully...