GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 16 Jan 2019, 21:06

Close

GMAT Club Daily Prep

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.

Close

Request Expert Reply

Confirm Cancel
Events & Promotions in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
  • The winning strategy for a high GRE score

     January 17, 2019

     January 17, 2019

     08:00 AM PST

     09:00 AM PST

    Learn the winning strategy for a high GRE score — what do people who reach a high score do differently? We're going to share insights, tips and strategies from data we've collected from over 50,000 students who used examPAL.
  • Free GMAT Strategy Webinar

     January 19, 2019

     January 19, 2019

     07:00 AM PST

     09:00 AM PST

    Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

If the area of triangular region RST is 25, what is the

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

 
Math Revolution GMAT Instructor
User avatar
V
Joined: 16 Aug 2015
Posts: 6806
GMAT 1: 760 Q51 V42
GPA: 3.82
Premium Member
Re: If the area of triangular region RST is 25, what is the  [#permalink]

Show Tags

New post 15 May 2018, 08:03
prasannar wrote:
If the area of triangular region RST is 25, what is the perimeter of RST?

(1) The length of one side of RST is \(5\sqrt{2}\).
(2) RST is a right isosceles triangle.



Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.

Assume b is the base and h is the height of the triangle.
(1/2)bh = 25.
Since we have 2 variables and 1 equation, D is most likely to be the answer. So, we should consider each of the conditions on their own first.

Condition 1)
Since there two cases, we can't determine the perimeter of RST.
We don't know which side is 5√2.
Those cases are b is 5√2 or another side length is 5√2.
This is not sufficient.

Condition 2)
Assume that the length of two legs is a.
The area of the right isosceles triangle is (1/2)a^2 = 25.
Then a = 5 and the hypotenuse is 5√2 .
The perimeter is 10 + 5√2.
Condition 2) is sufficient.

Therefore, the answer is B.

If the original condition includes “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations” etc., one more equation is required to answer the question. If each of conditions 1) and 2) provide an additional equation, there is a 59% chance that D is the answer, a 38% chance that A or B is the answer, and a 3% chance that the answer is C or E. Thus, answer D (conditions 1) and 2), when applied separately, are sufficient to answer the question) is most likely, but there may be cases where the answer is A,B,C or E.
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $149 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Senior DS Moderator
User avatar
V
Joined: 27 Oct 2017
Posts: 1195
Location: India
Concentration: International Business, General Management
GPA: 3.64
WE: Business Development (Energy and Utilities)
Premium Member CAT Tests
Re: If the area of triangular region RST is 25, what is the  [#permalink]

Show Tags

New post 29 Dec 2018, 09:03
Intern
Intern
avatar
B
Joined: 26 Jun 2018
Posts: 5
Location: India
CAT Tests
Re: If the area of triangular region RST is 25, what is the  [#permalink]

Show Tags

New post 02 Jan 2019, 11:19
Given, area of any triangle.
To find : its perimeter
So we need measurements of its sides somehow

S1: one side is given. It can be any side and further, no info about the type of triangle is given to help us find the other sides. So, NOT SUFFICIENT>

S2: type of triangle given . Combine this with area of the triangle. Base = height, and 0.5*base*height = 25
base = height = 5 root 2
thus, hypothenuse can also be determined using pythagoras theorem.
hence, the perimeter of the triangle can be determined.
so, S2 is SUFFICIENT
GMAT Club Bot
Re: If the area of triangular region RST is 25, what is the &nbs [#permalink] 02 Jan 2019, 11:19

Go to page   Previous    1   2   [ 23 posts ] 

Display posts from previous: Sort by

If the area of triangular region RST is 25, what is the

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.