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

It is currently 11 Dec 2018, 06:02

R1 Decisions:

HBS Chat - Decisions will be released at Noon ET  |  UVA Darden Chat  |  YouTube Live with Cornell Johnson @11am ET


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 December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
  • Free GMAT Prep Hour

     December 11, 2018

     December 11, 2018

     09:00 PM EST

     10:00 PM EST

    Strategies and techniques for approaching featured GMAT topics. December 11 at 9 PM EST.
  • The winning strategy for 700+ on the GMAT

     December 13, 2018

     December 13, 2018

     08:00 AM PST

     09:00 AM PST

    What people who reach the high 700's do differently? We're going to share insights, tips and strategies from data we collected on over 50,000 students who used examPAL.

Over the course of 8 races, a runner's finishing time was 5 seconds

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

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51098
Over the course of 8 races, a runner's finishing time was 5 seconds  [#permalink]

Show Tags

New post 08 Feb 2017, 01:02
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

45% (03:11) correct 55% (03:04) wrong based on 84 sessions

HideShow timer Statistics

Over the course of 8 races, a runner's finishing time was 5 seconds faster each race than the race prior. If her combined total for all 8 races was 44:20, what was her finishing time for the second race?

A. 5:30
B. 5:35
C. 5:40
D. 5:45
E. 5:50

_________________

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?
Extra-hard Quant Tests with Brilliant Analytics

Intern
Intern
avatar
B
Joined: 25 Dec 2016
Posts: 17
Location: United States (GA)
Concentration: Healthcare, Entrepreneurship
GMAT 1: 770 Q51 V42
GPA: 3.64
WE: Medicine and Health (Health Care)
Re: Over the course of 8 races, a runner's finishing time was 5 seconds  [#permalink]

Show Tags

New post 08 Feb 2017, 06:58
We know that the combined time for the races is 44:20 or 2660 seconds.

Since the runner's times decrease by 5 seconds per race, we can think of the final race as x seconds, the next to last race as x+5 seconds, the one before it as x+10, etc. These can be added together and rewritten as follows:

\(8x+5(1+2+3+4+5+6+7)=2660\)
\(8x=2520\)
\(x=315\)

So we know the final race was 315 seconds. We also know that the second race was 30 seconds longer than the final race. 315+30=345. We convert this to minutes to get 5:45. Answer is D.
Target Test Prep Representative
User avatar
P
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 4277
Location: United States (CA)
Re: Over the course of 8 races, a runner's finishing time was 5 seconds  [#permalink]

Show Tags

New post 13 Feb 2017, 07:39
1
Bunuel wrote:
Over the course of 8 races, a runner's finishing time was 5 seconds faster each race than the race prior. If her combined total for all 8 races was 44:20, what was her finishing time for the second race?

A. 5:30
B. 5:35
C. 5:40
D. 5:45
E. 5:50


Since in each race, the runner was 5 seconds faster (i.e., 5 seconds less) than in the race prior, we can let the time of each race be as follows:

Race 1 = x

Race 2 = x - 5

Race 3 = x - 10

Race 4 = x - 15

Race 5 = x - 20

Race 6 = x - 25

Race 7 = x - 30

Race 8 = x - 35

Thus, the sum of the race times is 8x - 140.

We are given that the total was 44 minutes and 20 seconds. Converting to seconds gives us:

44 minutes and 20 seconds = 44 x 60 + 20 seconds = 2660 seconds

We can now determine x:

8x - 140 = 2660

8x = 2800

x = 350 seconds

350 seconds = 350/60 = 5 and 50/60 minutes = 5 minutes and 50 seconds.

Thus, the time of the second race is 5 minutes 50 seconds - 5 seconds = 5 minutes and 45 seconds.

Answer: D
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Senior SC Moderator
User avatar
V
Joined: 14 Nov 2016
Posts: 1323
Location: Malaysia
GMAT ToolKit User Premium Member CAT Tests
Re: Over the course of 8 races, a runner's finishing time was 5 seconds  [#permalink]

Show Tags

New post 21 Feb 2017, 06:09
Bunuel wrote:
Over the course of 8 races, a runner's finishing time was 5 seconds faster each race than the race prior. If her combined total for all 8 races was 44:20, what was her finishing time for the second race?

A. 5:30
B. 5:35
C. 5:40
D. 5:45
E. 5:50


Official solution from Veritas Prep.

This word problem is essentially a sequence problem. You don't know what her time was for each individual race, but you can use the same variable (for example, x) and relate each race to the others. If her first race took her x seconds, then the second was (x - 5), the third was (x - 10), etc. So for 8 total races, that means that the sequence would go:
x, (x - 5), (x - 10), ..., (x - 35)

You can then sum the times quickly by recognizing that each of 8 races has its own x, so that means 8x. And then you'll subtract from all but the first race. That means that 7 races will involve subtraction, with the smallest number subtracted being 5 and the largest being 35. Since this is an evenly-spaced set, you can multiply those 7 terms by the average of 20, and know that her overall time can be represented as 8x - 140.

You know that \(8x - 140 = 2660\) (NOTE: You'll calculate 2660 by multiplying 44 minutes by 60 and adding the remaining 20 seconds. 40 times 60 is 2400, plus 4 times 60 is another 240, plus 20 gives you 2660).

That then means that \(8x = 2800\), which means that x (the time of her first race) equals 350 seconds. 350 seconds is 5:50, but keep in mind that that is the time of her FIRST race, and the question asks for her second. Subtracting 5, that means that her second race took her 5:45.
_________________

"Be challenged at EVERY MOMENT."

“Strength doesn’t come from what you can do. It comes from overcoming the things you once thought you couldn’t.”

"Each stage of the journey is crucial to attaining new heights of knowledge."

Rules for posting in verbal forum | Please DO NOT post short answer in your post!

Advanced Search : https://gmatclub.com/forum/advanced-search/

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 9114
Premium Member
Re: Over the course of 8 races, a runner's finishing time was 5 seconds  [#permalink]

Show Tags

New post 25 Mar 2018, 14:47
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.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

GMAT Club Bot
Re: Over the course of 8 races, a runner's finishing time was 5 seconds &nbs [#permalink] 25 Mar 2018, 14:47
Display posts from previous: Sort by

Over the course of 8 races, a runner's finishing time was 5 seconds

  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®.