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:

One hour after Yolanda started walking from X to Y, a [#permalink]

Show Tags

05 Jan 2006, 17:41

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

12. One hour after Yolanda started
walking from X to Y, a distance of 45
miles, Bob started walking along the
same road from Y to X. If Yolandaâ€™s
walking rate was 3 miles per hour and
Bobâ€™s was 4 miles per hour, how
many miles had Bob walked when
they met?

(A) 24
(B) 23
(C) 22
(D) 21
(E) 19.5

I believe that the answer that the official guide gives is not very precise...According to other books the process for solving questions like this is the following:

We add the rates of Yolanda and Bob--> 4+3=7
and then we divide this sum with the distance they have to cover in order to meet->
45/7= 6,43
this means that they have to walk for 6,43 hours (6 hours and (43x60)/100 minutes) in order to meet...

Bob, in 6 hours and 25,8 minutes can walk:

1 hour-->4miles
6h and 25,8 m-->25,032 miles

but this choice is not available at the OG...
The official answer is A and the explanation they give is the following:

Let t be the number of hours that Bob had
walked when he met Yolanda. Then,
when they met, Bob had walked 4t
miles and Yolanda had walked 3(t + 1)
miles. These distances must sum to 45
miles, so 4t + 3(t + 1) = 45, which
may be solved for t as follows. 4t + 3(t
+ 1) = 45, 4t + 3t + 3 =45, 7t = 42, so t
= 6 (hours). Therefore, Bob had
walked 4t = 4(6) = 24 miles when they
met. A is the correct answer.

Which one is the correct method? Which one should I use? I don't even understand why (in the OG) Yolanda had walked: 3(t+1) miles...

I hour after yolanda has started walking means Yolanda has covered 3 miles which means distance between bob and yolanda is 45-3 = 42 miles.

Relative velocity = 4+3 = 7 mph therefore they will take 42/7 = 6 hrs to meet at which me yolanda would have walked 3 x 6 = 18 miles and Bob would have walked 4*6= 24 . Therefore no ambiguity it A 24 miles

From X-Y, Yolanda covers 3 miles every hour. From Y-X, Bob covers 4 miles every hour. So for this 45 mile gap between them, every hour, 7 miles is trimmed off.

So it would take 45/7 = ~6 hours to meet. By this time, Bob must have walked 4*6 = 24 miles.

I hour after yolanda has started walking means Yolanda has covered 3 miles which means distance between bob and yolanda is 45-3 = 42 miles.

Relative velocity = 4+3 = 7 mph therefore they will take 42/7 = 6 hrs to meet at which me yolanda would have walked 3 x 6 = 18 miles and Bob would have walked 4*6= 24 . Therefore no ambiguity it A 24 miles

Hope this helps

I didn't notice that they didn't start walking at the same time...
Thank you very much!