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:

A total of 512 players participated in a single tennis knock [#permalink]

Show Tags

01 May 2012, 21:26

3

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

35% (medium)

Question Stats:

67% (02:11) correct
33% (01:17) wrong based on 291 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!

Re: A total of 512 players participated in a single tennis knock [#permalink]

Show Tags

01 May 2012, 23:00

2

This post received KUDOS

Expert's post

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.

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

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

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.

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!

Re: A total of 512 players participated in a single tennis knock [#permalink]

Show Tags

20 Apr 2015, 04:47

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. _________________

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

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

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 needed

Either way answer will be the same but the best thing/strategy is to solve the problems within minimum time & calculation _________________

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 _________________

Give me a hell yeah ...!!!!!

gmatclubot

Re: A total of 512 players participated in a single tennis knock
[#permalink]
22 Apr 2016, 14:59

Excellent posts dLo saw your blog too..!! Man .. you have got some writing skills. And Just to make an argument = You had such an amazing resume ; i am glad...

So Much $$$ Business school costs a lot. This is obvious, whether you are a full-ride scholarship student or are paying fully out-of-pocket. Aside from the (constantly rising)...

They say you get better at doing something by doing it. then doing it again ... and again ... and again, and you keep doing it until one day you look...

I barely remember taking decent rest in the last 60 hours. It’s been relentless with submissions, birthday celebration, exams, vacating the flat, meeting people before leaving and of...