Author 
Message 
TAGS:

Hide Tags

Intern
Joined: 04 Mar 2012
Posts: 47

A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
01 May 2012, 21:26
Question Stats:
69% (01:11) correct 31% (01:21) wrong based on 450 sessions
HideShow timer Statistics
A total of 512 players participated in a single tennis knock out tournament. What is the total number of matches played in the tournament? (Knockout means if a player loses, he is out of the tournament). No match ends in a tie. A. 511 B. 512 C. 256 D. 255 E. 1023 I chose D, solved this way  after first 256 matches, remaing players 256 (those 256 who lost are knocked out), after another 128 matches, remaining players are 128, after 64 more matches, no of remainig players are 64, after 32, 32, after 16, 16, after 8, 8, after 4, 4, after 2,2, and then 1  total 256 + 128+64+32+16+8+1 = 255 matches However, the correct answer given is A 511, can anyone please exlain what's wrong in my approach? Thanks!
Official Answer and Stats are available only to registered users. Register/ Login.




Intern
Joined: 25 Jun 2012
Posts: 36

Re: A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
19 Nov 2012, 19:17
There are 512 players, only 1 person wins, 511 players lose. in order to lose, you must have lost a game.
511 games.




Math Expert
Joined: 02 Sep 2009
Posts: 47977

Re: A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
01 May 2012, 23:00
gmihir wrote: A total of 512 players participated in a single tennis knock out tournament. What is the total number of matches played in the tournament? (Knockout means if a player loses, he is out of the tournament). No match ends in a tie.
A. 511 B. 512 C. 256 D. 255 E. 1023
I chose D, solved this way  after first 256 matches, remaing players 256 (those 256 who lost are knocked out), after another 128 matches, remaining players are 128, after 64 more matches, no of remainig players are 64, after 32, 32, after 16, 16, after 8, 8, after 4, 4, after 2,2, and then 1  total 256 + 128+64+32+16+8+1 = 255 matches
However, the correct answer given is A 511, can anyone please exlain what's wrong in my approach? Thanks! You've done everything right except calculation: 256+128+64+32+16+8+4+2+1=511. Answer: A.
_________________
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: 22 Jan 2013
Posts: 9

Re: A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
26 Feb 2013, 19:12
1 the 512 players will play 256 games > 256 plyers will go out from these games 2 the remaining is 256 players, they will play 128 games > 128 players will go out 3 the remaining is 128 players, they will play 64 games > 64 players will go out 4 the remaining is 64 players, they will play 32 games > 32 players will go out 5 the remaining is 32 players, they will play 16 games > 16 players will go out 6 the remaining is 16 players, they will play 8 games > 8 players will go out 7 the remaining is 8 players, they will play 4 games > 4 players will go out 8 the remaining is 4 players, they will play 2 games > 2 players will go out. 9 the remaining is 2 players, they will play 1 games > 1 players will go out
265+128+64+32+16+8+4+2+1=511



Intern
Joined: 05 Feb 2013
Posts: 9

Re: A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
27 Feb 2013, 12:44
AlyoshaKaramazov wrote: There are 512 players, only 1 person wins, 511 players lose. in order to lose, you must have lost a game.
511 games. I know this is an old post. But damn, sometimes the answer is so simple, you just have to thinkg logically. Thanks Alyosha



Intern
Joined: 31 May 2013
Posts: 13

Re: A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
24 Jun 2013, 08:23
If you divide 512 by 2 recursively to factor: 512,256,128,64,32,16,8,4,2,1. so the answer narrows to down to either A or B. Since the last dividend is 1, the sum will be odd so it should be 511
A



SVP
Joined: 06 Sep 2013
Posts: 1851
Concentration: Finance

Re: A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
26 Dec 2013, 13:05
Bunuel wrote: gmihir wrote: A total of 512 players participated in a single tennis knock out tournament. What is the total number of matches played in the tournament? (Knockout means if a player loses, he is out of the tournament). No match ends in a tie.
A. 511 B. 512 C. 256 D. 255 E. 1023
I chose D, solved this way  after first 256 matches, remaing players 256 (those 256 who lost are knocked out), after another 128 matches, remaining players are 128, after 64 more matches, no of remainig players are 64, after 32, 32, after 16, 16, after 8, 8, after 4, 4, after 2,2, and then 1  total 256 + 128+64+32+16+8+1 = 255 matches
However, the correct answer given is A 511, can anyone please exlain what's wrong in my approach? Thanks! You've done everything right except calculation: 256+128+64+32+16+8+4+2+1=511. Answer: A. Geometric progression 512 = 2^9 2^1 + 2^2 ....+2^9 + 1 2 ( 2^81) = 2^9  2 + 1 A is our friend here Cheers! J



Manager
Joined: 28 Apr 2013
Posts: 143
Location: India
GPA: 4
WE: Medicine and Health (Health Care)

Re: A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
03 Jan 2014, 17:34
gmihir wrote: A total of 512 players participated in a single tennis knock out tournament. What is the total number of matches played in the tournament? (Knockout means if a player loses, he is out of the tournament). No match ends in a tie.
A. 511 B. 512 C. 256 D. 255 E. 1023
I chose D, solved this way  after first 256 matches, remaing players 256 (those 256 who lost are knocked out), after another 128 matches, remaining players are 128, after 64 more matches, no of remainig players are 64, after 32, 32, after 16, 16, after 8, 8, after 4, 4, after 2,2, and then 1  total 256 + 128+64+32+16+8+1 = 255 matches
However, the correct answer given is A 511, can anyone please exlain what's wrong in my approach? Thanks! 256+128+ 64+32+16+8+4+2+1 = 511 OA  A Thanks for posting
_________________
Thanks for Posting
LEARN TO ANALYSE
+1 kudos if you like



Intern
Joined: 17 May 2015
Posts: 2

A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
25 Jun 2015, 02:14
One of the best logics I've seen for these knockout questions is as follows: In this question, there are 512 participants. And it takes ONE match to eliminate ONE player. So at the end of the day you need to eliminate everyone except the winner. ie. you need to eliminate 511 participants and naturally you need 511 matches for the same



Manager
Joined: 09 Jun 2015
Posts: 97

Re: A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
18 Apr 2016, 01:13
gmihir wrote: A total of 512 players participated in a single tennis knock out tournament. What is the total number of matches played in the tournament? (Knockout means if a player loses, he is out of the tournament). No match ends in a tie.
A. 511 B. 512 C. 256 D. 255 E. 1023
I chose D, solved this way  after first 256 matches, remaing players 256 (those 256 who lost are knocked out), after another 128 matches, remaining players are 128, after 64 more matches, no of remainig players are 64, after 32, 32, after 16, 16, after 8, 8, after 4, 4, after 2,2, and then 1  total 256 + 128+64+32+16+8+1 = 255 matches
However, the correct answer given is A 511, can anyone please exlain what's wrong in my approach? Thanks! If there are 2 players, then there will be only 1 match If there are 4 players, then there will be 2+1 matches 8 players, 4+2+1=7 16 players, 8+4+2+1 = 15 Now you are getting the pattern 512 players, 256+128+64+..+2+1=511



Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 3773
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)

Re: A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
18 Apr 2016, 12:01
Mathivanan Palraj wrote: gmihir wrote: A total of 512 players participated in a single tennis knock out tournament. What is the total number of matches played in the tournament? (Knockout means if a player loses, he is out of the tournament). No match ends in a tie.
A. 511 B. 512 C. 256 D. 255 E. 1023
I chose D, solved this way  after first 256 matches, remaing players 256 (those 256 who lost are knocked out), after another 128 matches, remaining players are 128, after 64 more matches, no of remainig players are 64, after 32, 32, after 16, 16, after 8, 8, after 4, 4, after 2,2, and then 1  total 256 + 128+64+32+16+8+1 = 255 matches
However, the correct answer given is A 511, can anyone please exlain what's wrong in my approach? Thanks! If there are 2 players, then there will be only 1 match If there are 4 players, then there will be 2+1 matches 8 players, 4+2+1=7 16 players, 8+4+2+1 = 15 Now you are getting the pattern 512 players, 256+128+64+..+2+1=511 Good catch , or U can go the other way round  When there are 2 player only 1 knockout match is needed When there are 3 player only 2 knockout match is needed When there are 4 player only 3 knockout match is needed So, the pattern formed is  When there are n player only n  1 knockout match is needed Hence , When there are 512 player only 511 (512  1 ) knockout match is neededEither way answer will be the same but the best thing/strategy is to solve the problems within minimum time & calculation
_________________
Thanks and Regards
Abhishek....
PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS
How to use Search Function in GMAT Club  Rules for Posting in QA forum  Writing Mathematical Formulas Rules for Posting in VA forum  Request Expert's Reply ( VA Forum Only )



BSchool Forum Moderator
Joined: 12 Aug 2015
Posts: 2649

Re: A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
22 Apr 2016, 14:59
Firstly the question should state that a match is played between 2 players (what if its a cricket match) assuming the match is played between 2 teams = > number of matches => 512/2 + 256/2 +128/2+64/2+32/2+16/2+8/2+4/2+2/2 we dont need to calculate the sum here => the unit digit will be 1 SMASH that A
_________________
MBA Financing: INDIAN PUBLIC BANKS vs PRODIGY FINANCE! Getting into HOLLYWOOD with an MBA! The MOST AFFORDABLE MBA programs!STONECOLD's BRUTAL Mock Tests for GMATQuant(700+)AVERAGE GRE Scores At The Top Business Schools!



Senior Manager
Joined: 18 Jun 2016
Posts: 269
Location: India
GMAT 1: 720 Q50 V38 GMAT 2: 750 Q49 V42
GPA: 4
WE: General Management (Other)

Re: A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
31 Aug 2016, 10:54
stonecold wrote: Firstly the question should state that a match is played between 2 players (what if its a cricket match) assuming the match is played between 2 teams = > number of matches => 512/2 + 256/2 +128/2+64/2+32/2+16/2+8/2+4/2+2/2 we dont need to calculate the sum here => the unit digit will be 1 SMASH that A 1. Question mentions that it is a Tennis Tournament of Singles. 2. All we know is that the sum is Odd. Please explain how will you get the unit's digit = 1 by looking at the sequence. My Solution: # of matches = 256 + 128 + 64 + ... + 2 + 1 = \(2^8 + 2^7 + 2^6 + ... + 2^1 + 2^0\) => Ascending G.P. Sum of G.P. =\(\frac{a(r^n  1)}{a1}\) Where, a = First Term = 1 (Sum starts from 1) r = Common Ratio = 2 (ratio of each successive term is 2) n = Number of terms = 9 Therefore, Sum = \(\frac{1 * (2^9  1)}{21}\) = 512  1 = 511
_________________
I'd appreciate learning about the grammatical errors in my posts
Please hit Kudos If my Solution helps
My Debrief for 750  https://gmatclub.com/forum/from720to750oneofthemostdifficultpleatuestoovercome246420.html
My CR notes  https://gmatclub.com/forum/patternsincrquestions243450.html



NonHuman User
Joined: 09 Sep 2013
Posts: 7748

Re: A total of 512 players participated in a single tennis knock
[#permalink]
Show Tags
19 Dec 2017, 14:54
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources




Re: A total of 512 players participated in a single tennis knock &nbs
[#permalink]
19 Dec 2017, 14:54






