Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 46305

What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
14 Jun 2012, 03:13
Question Stats:
68% (00:34) correct 32% (00:29) wrong based on 1081 sessions
HideShow timer Statistics



Math Expert
Joined: 02 Sep 2009
Posts: 46305

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
14 Jun 2012, 03:14



Current Student
Joined: 29 Mar 2012
Posts: 317
Location: India
GMAT 1: 640 Q50 V26 GMAT 2: 660 Q50 V28 GMAT 3: 730 Q50 V38

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
Updated on: 14 Jun 2012, 04:40
Hi,
Difficulty level: close to 600. ('cause at first glance, I said, answer is (C). Then, when I actually solved, I got the right answer.)
Perimeter of isosceles triangle MNP?
Using (1), MN = 16, no idea about NP & MP. Insufficient.
Using (2) NP = 20, no idea about MN & MP. Insufficient.
Combining both the statements, MN = 16 & NP = 20 for MNP to be isosceles, the third side MP can be 16 or 20. Insufficient.
Thus, Answer is (E).
Regards,
Originally posted by cyberjadugar on 14 Jun 2012, 04:16.
Last edited by cyberjadugar on 14 Jun 2012, 04:40, edited 1 time in total.



Math Expert
Joined: 02 Sep 2009
Posts: 46305

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
14 Jun 2012, 04:30
cyberjadugar wrote: Hi,
Perimeter of isosceles triangle MNP?
Using (1), MN = 16, no idea about NP & MP. Insufficient.
Using (2) NP = 20, no idea about MN & MP. Insufficient.
Combining both the statements, MN = 16 & NP = 20 for MNP to be isosceles, the third side MP can be 16 or 20. Insufficient.
Thus, Answer is (E).
Regards, Just a bit harder question, based on OG#28: What is the perimeter of isosceles triangle MNP?(1) MN = 16 (2) NP = 32 What would be the answer in this case?
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Current Student
Joined: 29 Mar 2012
Posts: 317
Location: India
GMAT 1: 640 Q50 V26 GMAT 2: 660 Q50 V28 GMAT 3: 730 Q50 V38

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
14 Jun 2012, 04:38
Bunuel wrote: cyberjadugar wrote: Hi,
Perimeter of isosceles triangle MNP?
Using (1), MN = 16, no idea about NP & MP. Insufficient.
Using (2) NP = 20, no idea about MN & MP. Insufficient.
Combining both the statements, MN = 16 & NP = 20 for MNP to be isosceles, the third side MP can be 16 or 20. Insufficient.
Thus, Answer is (E).
Regards, Just a bit harder question, based on OG#28: What is the perimeter of isosceles triangle MNP?(1) MN = 16 (2) NP = 32 What would be the answer in this case? Hi, Using (1) & (2) alone we can't get the answer (similar to the explanation above) Combinig (1) & (2), MN = 16 & NP = 32 Possible sides of triangle (16, 16, 32) & (16, 32, 32), now we know a+b>c (sum of two sides greater than third side) (16, 16, 32) doesn't fulfill this criteria Thus only possible triangle is (16, 32, 32) perimeter = 80 Thus, Answer is (C) Regards,



Math Expert
Joined: 02 Sep 2009
Posts: 46305

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
14 Jun 2012, 04:46
cyberjadugar wrote: Bunuel wrote: cyberjadugar wrote: Hi,
Perimeter of isosceles triangle MNP?
Using (1), MN = 16, no idea about NP & MP. Insufficient.
Using (2) NP = 20, no idea about MN & MP. Insufficient.
Combining both the statements, MN = 16 & NP = 20 for MNP to be isosceles, the third side MP can be 16 or 20. Insufficient.
Thus, Answer is (E).
Regards, Just a bit harder question, based on OG#28: What is the perimeter of isosceles triangle MNP?(1) MN = 16 (2) NP = 32 What would be the answer in this case? Hi, Using (1) & (2) alone we can't get the answer (similar to the explanation above) Combinig (1) & (2), MN = 16 & NP = 32 Possible sides of triangle (16, 16, 32) & (16, 32, 32), now we know a+b>c (sum of two sides greater than third side) (16, 16, 32) doesn't fulfill this criteria Thus only possible triangle is (16, 32, 32) perimeter = 80 Thus, Answer is (C) Regards, Correct. What is the perimeter of isosceles triangle MNP?(1) MN = 16 (2) NP = 32 MUST KNOW FOR THE GMAT: The length of any side of a triangle must be larger than the positive difference of the other two sides, but smaller than the sum of the other two sides. When we consider the two statements together we can see that the case of {16, 16, 32} is not possible since the sum of two sides (16 and 16) is not greater then the third side (32), so only the following case is possible: {16, 32, 32}, which gives the perimeter equal to 16+32+32=80. Answer: C. For more on Triangles check: mathtriangles87197.html (Theory, Formulas, Tricks, and Tips). Hope it helps.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Manager
Joined: 07 Sep 2011
Posts: 61
Location: United States
Concentration: Strategy, International Business
WE: General Management (Real Estate)

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
16 Jun 2012, 05:15
Higher then 550 for sure. I think 600.
Unless we know the property "The length of any side of a triangle must be larger than the positive difference of the other two sides, but smaller than the sum of the other two sides", we can not answer the question easily.
Stmt 1: We can know the second side but don't know the length of third side. Stmt 2: Same logic as given for stmt 1.
Together the third side can be 16 or it can be 20 also.
E



Math Expert
Joined: 02 Sep 2009
Posts: 46305

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
22 Jun 2012, 04:02



Senior Manager
Status: Final Countdown
Joined: 17 Mar 2010
Posts: 495
Location: India
GPA: 3.82
WE: Account Management (Retail Banking)

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
23 Jul 2012, 07:47
What is the perimeter of isosceles triangle MNP? PERIMETER=MN+NP+MP Not given which sides are equal (1) MN = 16 NP&MP unavailable so insufficient (2) NP = 20 MN&MP unavailable so insufficient from (i)&(ii) Perimeter=MN+NP+MP=16+20+?, we don't know which two sides are equal;insufficient (E)
_________________
" Make more efforts " Press Kudos if you liked my post



Manager
Joined: 12 Jan 2013
Posts: 188

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
09 Jan 2014, 10:16
Bunuel wrote: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectWhat is the perimeter of isosceles triangle MNP? (1) MN = 16 (2) NP = 20 Diagnostic Test Question: 28 Page: 25 Difficulty: 550 Sides of an isosceles triangle: a, a, b.. We don't know if a = 16 or if a = 20, so E



Current Student
Joined: 13 Sep 2014
Posts: 13
Location: China
Concentration: General Management, Operations

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
12 Dec 2014, 02:34
Bunuel wrote: What is the perimeter of isosceles triangle MNP? (1) MN = 16 (2) NP = 20 Diagnostic Test Question: 28 Page: 25 Difficulty: 550 Hi all, when reading "What is the perimeter of Isosceles Triangle MNP", how can I be sure that "MNP" stands for the vertices (as it is the case here) and not for the sides? If M, N and P each were sides, the result to the question in my opinion would change to "C", as M*N and N*P would HAVE to account for 4*4 and 4*5 in this logic as we're dealing with an isosceles and the rule for the sum of two triangle sides doesn't allow any other solution. How can I identify these variables to be representing vertices instead of sides? Thanks Christian



Math Expert
Joined: 02 Sep 2009
Posts: 46305

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
12 Dec 2014, 06:45
christian1904 wrote: Bunuel wrote: What is the perimeter of isosceles triangle MNP? (1) MN = 16 (2) NP = 20 Diagnostic Test Question: 28 Page: 25 Difficulty: 550 Hi all, when reading "What is the perimeter of Isosceles Triangle MNP", how can I be sure that "MNP" stands for the vertices (as it is the case here) and not for the sides? If M, N and P each were sides, the result to the question in my opinion would change to "C", as M*N and N*P would HAVE to account for 4*4 and 4*5 in this logic as we're dealing with an isosceles and the rule for the sum of two triangle sides doesn't allow any other solution. How can I identify these variables to be representing vertices instead of sides? Thanks Christian You are overthinking this one. Capital letters refer to vertices.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Intern
Joined: 28 Jul 2014
Posts: 9

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
22 Dec 2014, 11:12
Bunuel wrote: christian1904 wrote: Bunuel wrote: What is the perimeter of isosceles triangle MNP? (1) MN = 16 (2) NP = 20 Diagnostic Test Question: 28 Page: 25 Difficulty: 550 Hi all, when reading "What is the perimeter of Isosceles Triangle MNP", how can I be sure that "MNP" stands for the vertices (as it is the case here) and not for the sides? If M, N and P each were sides, the result to the question in my opinion would change to "C", as M*N and N*P would HAVE to account for 4*4 and 4*5 in this logic as we're dealing with an isosceles and the rule for the sum of two triangle sides doesn't allow any other solution. How can I identify these variables to be representing vertices instead of sides? Thanks Christian You are overthinking this one. Capital letters refer to vertices. Would the angle rules of isosceles triangles not apply here? Since we know sides of 16, 20  would the remaining side not have to be 16 in order to maintain 1:1:\sqrt{2} ???



Director
Status: Professional GMAT Tutor
Affiliations: AB, cum laude, Harvard University (Class of '02)
Joined: 10 Jul 2015
Posts: 646
Location: United States (CA)
Age: 38
GMAT 1: 770 Q47 V48 GMAT 2: 730 Q44 V47 GMAT 3: 750 Q50 V42
GRE 1: 337 Q168 V169
WE: Education (Education)

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
27 Mar 2016, 19:45
Here is a visual that should help.
Attachments
Screen Shot 20160327 at 7.44.30 PM.png [ 87.61 KiB  Viewed 10070 times ]
_________________
Harvard grad and 99% GMAT scorer, offering expert, private GMAT tutoring and coaching, both inperson (San Diego, CA, USA) and online worldwide, since 2002.
One of the only known humans to have taken the GMAT 5 times and scored in the 700s every time (700, 710, 730, 750, 770), including verified section scores of Q50 / V47, as well as personal bests of 8/8 IR (2 times), 6/6 AWA (4 times), 50/51Q and 48/51V (1 question wrong).
You can download my official testtaker score report (all scores within the last 5 years) directly from the Pearson Vue website: https://tinyurl.com/y8zh6qby Date of Birth: 09 December 1979.
GMAT Action Plan and Free EBook  McElroy Tutoring



Manager
Joined: 07 Jun 2017
Posts: 174
Location: India
Concentration: Technology, General Management
GPA: 3.6
WE: Information Technology (Computer Software)

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
12 Sep 2017, 21:37
Isosceles Triangle  > first glance I thought answer is C but after solving got the correct answer there are 2 answer with So answer should be E
_________________
Regards, Naveen email: nkmungila@gmail.com Please press kudos if you like this post



Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2570

Re: What is the perimeter of isosceles triangle MNP? [#permalink]
Show Tags
18 May 2018, 11:36
Bunuel wrote: What is the perimeter of isosceles triangle MNP?
(1) MN = 16 (2) NP = 20 Statement One Alone: MN = 16 Since we don’t know anything about NP and MP, statement one alone is not sufficient. Statement Two Alone: NP = 20 Since we don’t know anything about MN and MP, statement two alone is not sufficient. Statements One and Two Together: With two statements together, we know that MN = 16 and NP = 20. Since triangle MNP is isosceles, MP could be 16 or it could be 20. If MP is 16, then the perimeter is 16 x 2 + 20 = 52. However, if MP is 20, then the perimeter is 20 x 2 + 16 = 56. Since we don’t have a unique number for the perimeter, the two statements together are still not sufficient to answer the question. Answer: E
_________________
Jeffery Miller
Head of GMAT Instruction
GMAT Quant SelfStudy Course
500+ lessons 3000+ practice problems 800+ HD solutions




Re: What is the perimeter of isosceles triangle MNP?
[#permalink]
18 May 2018, 11:36






