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

It is currently 19 Nov 2018, 21:48

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 November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
  • How to QUICKLY Solve GMAT Questions - GMAT Club Chat

     November 20, 2018

     November 20, 2018

     09:00 AM PST

     10:00 AM PST

    The reward for signing up with the registration form and attending the chat is: 6 free examPAL quizzes to practice your new skills after the chat.
  • The winning strategy for 700+ on the GMAT

     November 20, 2018

     November 20, 2018

     06:00 PM EST

     07:00 PM EST

    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.

Bob and Wendy planned to walk from their home to a

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

Hide Tags

Manager
Manager
avatar
Joined: 08 Oct 2009
Posts: 64
Location: Denver, CO
WE 1: IT Business Analyst-Building Materials Industry
Bob and Wendy planned to walk from their home to a  [#permalink]

Show Tags

New post 26 Jan 2010, 20:01
3
9
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

72% (01:16) correct 28% (01:12) wrong based on 611 sessions

HideShow timer Statistics

Bob and Wendy planned to walk from their home to a restaurant for dinner together. However, Bob was delayed at work, and Wendy left for the restaurant before Bob did. If the restaurant is 3 miles from their home and Bob left for the restaurant a half-hour after Wendy did, how long did Wendy have to wait for Bob at the restaurant?

(1) Wendy walked at a constant pace of 4 miles per hour

(2) Bob walked at a constant pace of 1 mile per hour faster than Wendy.
Most Helpful Expert Reply
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50672
Re: MGMAT DS, Rates Need a better explanation  [#permalink]

Show Tags

New post 27 Jan 2010, 04:12
8
8
trzaskm wrote:
Bob and Wendy planned to walk from their home to a restaurant for dinner together. However, Bob was delayed at work, and Wendy left for the restaurant before Bob did. If the restaurant is 3 miles from their home and Bob left for the restaurant a half-hour after Wendy did, how long did Wendy have to wait for Bob at the restaurant?

(1) Wendy walked at a constant pace of 4 miles per hour

(2) Bob walked at a constant pace of 1 mile per hour faster than Wendy.

OA to Come


\(t=(\frac{3}{b}+\frac{1}{2})-\frac{3}{w}\), where \(t\) is the waiting time for Wendy, \(b\) is the Bob's rate and \(w\) is the Wendy's rate.

Hence we need both \(b\) and \(w\), to calculate \(t\).

(1) Gives us \(w=4\), \(b=?\), not sufficient;
(2) Gives us the relationship between \(w\) and \(b\), \(w+1=b\). Still insufficient, we should know the exact numerical value of at least one of them.

(1)+(2) From (1) we know \(w\), hence from (2) we can get \(b\). Sufficient.

Just to illustrate: \(t=(\frac{3}{b}+\frac{1}{2})-\frac{3}{w}=(\frac{3}{4+1}+\frac{1}{2})-\frac{3}{4}=\frac{7}{20}\), \(21\) min. Sufficient.

Answer: C.
_________________

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

General Discussion
Senior Manager
Senior Manager
User avatar
Joined: 13 May 2013
Posts: 428
Re: Bob and Wendy planned to walk from their home to a  [#permalink]

Show Tags

New post 30 Jul 2013, 13:33
1
Bob and Wendy planned to walk from their home to a restaurant for dinner together. However, Bob was delayed at work, and Wendy left for the restaurant before Bob did. If the restaurant is 3 miles from their home and Bob left for the restaurant a half-hour after Wendy did, how long did Wendy have to wait for Bob at the restaurant?

(1) Wendy walked at a constant pace of 4 miles per hour
Time = Distance/Rate
Time = 3/4
It took her 3/4ths of an hour (45 minutes) to get to the restaurant.

Still, we know nothing about about the rate at which Bob traveled after Wendy left.
INSUFFICIENT

(2) Bob walked at a constant pace of 1 mile per hour faster than Wendy.

We don't know Wendy's rate so we don't know Bob's either.
INSUFFICIENT

1+2)

Wendy rate = 4 miles/hour
Bob rate = 4+1 miles/hour

Time = Distance/Rate
Time = 3/5
It took him 3/5ths of an hour (36 minutes) to get to the restaurant.

She takes 45 minutes to get to the restaurant. Bob leaves when she is 15 minutes away. It takes him 36 minutes to get there from the point when she is 15 minutes away. In 15 minutes she is at the restaurant and bob is 36-15=21 minutes away.

She waits for 21 minutes.
SUFFICIENT

(C)
Intern
Intern
avatar
Joined: 02 Feb 2011
Posts: 38
Re: Bob and Wendy planned to walk from their home to a  [#permalink]

Show Tags

New post 29 Jan 2016, 05:43
I didnt understand why statement 1/2 alone arent sufficient. Please let me know where am I going wrong

Question interpretation:
Wendy reached in 't'
Since Bob started late half an hr therefore Bob must have reached in t+1/2

Statement 1:- Given Wendy's speed is 4

therefore we can calculate t since we know the distance = 3
Once we get t we can find time taken by Bob as well

Statement 2 : -
s= speed of Wendy
we know for Bob = (s+1) (t+1/2)=3
for Wendy = s(t )=3

If we equate both we can find t .

Where am I going wrong? Why cant we relate Bob & Wendy's time?
Manhattan Prep Instructor
User avatar
S
Joined: 22 Mar 2011
Posts: 1338
Re: Bob and Wendy planned to walk from their home to a  [#permalink]

Show Tags

New post 30 Jan 2016, 00:01
1
Seemachandran, your solution requires us to assume that Bob takes the same amount of time to make the trip as Wendy. Without the statements, we know nothing about this. So he may arrive hours later or just a short time after Wendy--we have no idea. (Also, be careful with your equation: we don't want to multiply Bob's speed by (t+1/2), since he isn't walking during that half hour. His speed during that time is zero!)

Statement 1 tells us nothing about Bob, so there is no way to solve.

Statement 2 tells us that Bob is 1 mph faster than Wendy, but that's not sufficient. Here are a few possibilities:

Wendy's rate is 5 mph and Bob's is 6 mph. Her walk is 36 min and Bob's is 30 min. Since she left 30 min earlier, he arrives 24 minutes after her.
Wendy's rate is 4 mph and Bob's is 5 mph. Her walk is 45 min and Bob's is 36 min. Since she left 30 min earlier, he arrives 21 minutes after her.

More than one possibility? This is insufficient, but if we combine 1&2 we get the second possibility above. Sufficient!
_________________


Dmitry Farber | Manhattan GMAT Instructor | New York


Manhattan GMAT Discount | Manhattan GMAT Course Reviews | View Instructor Profile |
Manhattan GMAT Reviews

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 8846
Premium Member
Re: Bob and Wendy planned to walk from their home to a  [#permalink]

Show Tags

New post 01 Nov 2018, 07:47
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: Bob and Wendy planned to walk from their home to a &nbs [#permalink] 01 Nov 2018, 07:47
Display posts from previous: Sort by

Bob and Wendy planned to walk from their home to a

  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®.