Welcome! Check out our free B-School Guides to learn how you compare with other applicants.

## rate problem

This topic has 1 expert reply and 4 member replies
finance Really wants to Beat The GMAT!
Joined
08 Mar 2011
Posted:
150 messages
Thanked:
3 times
rate problem Mon Jul 18, 2011 5:28 am
Elapsed Time: 00:00
• Lap #[LAPCOUNT] ([LAPTIME])
Two cars A and B start from Boston and New York respectively simultaneously and travel towards each other at constant speeds along the same route. After meeting at a point between Boston and New York the two cars A and B proceed to their respective destinations of New York and Boston. Car A reaches New York 40 minutes after the two cars have met and Car B reaches Boston 90 minutes after they have met. How long did Car A take to cover the distance between Boston and New York?

A. 1 hour

B. 1 hour 10 minutes

C. 2 hours 30 minutes

D. 1 hour 40 minutes

E. 2 hours 10 minutes

Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums!
amit2k9 GMAT Destroyer!
Joined
10 May 2011
Posted:
461 messages
Followed by:
2 members
Thanked:
35 times
Mon Jul 18, 2011 7:43 am
t be the time when A and B meet up.
d be the total distance between the two cities.
A and B be the individual speeds.

thus, At+ Bt = d
also, At+ 2/3* A = d
and Bt+3/2* B = d

thus, At+Bt = At+2/3 * A gives Bt = 2/3*A
and At+Bt = Bt+3/2*B gives At = 3/2 * B

hence, At = A/t * 2/3 * 3/2 gives t=1.

thus total time for A is 1hr +40 mins.

_________________
For Understanding Sustainability,Green Businesses and Social Entrepreneurship visit -http://aamthoughts.blogspot.com/
(Featured Best Green Site Worldwide-http://bloggers.com/green/popular/page2)

newgmattest Rising GMAT Star
Joined
18 May 2011
Posted:
52 messages
Thanked:
4 times
Mon Jul 18, 2011 10:15 pm

finance Really wants to Beat The GMAT!
Joined
08 Mar 2011
Posted:
150 messages
Thanked:
3 times
Mon Jul 18, 2011 11:42 pm
amit2k9 wrote:
also, At+ 2/3* A = d
and Bt+3/2* B = d

I didn't get this part. What is 2/3*A?? How did you find 3/2 * B??

### GMAT/MBA Expert

GMATGuruNY GMAT Instructor
Joined
25 May 2010
Posted:
6083 messages
Followed by:
1033 members
Thanked:
5243 times
GMAT Score:
790
Tue Jul 19, 2011 3:52 am
finance wrote:
Two cars A and B start from Boston and New York respectively simultaneously and travel towards each other at constant speeds along the same route. After meeting at a point between Boston and New York the two cars A and B proceed to their respective destinations of New York and Boston. Car A reaches New York 40 minutes after the two cars have met and Car B reaches Boston 90 minutes after they have met. How long did Car A take to cover the distance between Boston and New York?

A. 1 hour

B. 1 hour 10 minutes

C. 2 hours 30 minutes

D. 1 hour 40 minutes

E. 2 hours 10 minutes
We can plug in the answers, which represent the time for A to travel the entire distance.

We should start with the median amount of time, 1 hour + 40 minutes.

Answer choice D: Total time for A = 100 minutes.
Since A travels for 40 minutes after A and B meet, time for A and B to meet = 100-40 = 60 minutes.
Since B travels for 90 minutes after A and B meet, total time for B = 60+90 = 150 minutes.
Let distance = 300 miles.
Rate for A = d/t = 300/100 = 3 miles per minute.
Rate for B = d/t = 300/150 = 2 miles per minute.
When elements work together to cover a distance, we add their rates.
Combined rate for A and B = 3+2 = 5 miles per minute.
Time for A and B to meet = d/r = 300/5 = 60 minutes. Success!

_________________
Mitch Hunt
GMAT Private Tutor and Instructor
GMATGuruNY@gmail.com
If you find one of my posts helpful, please take a moment to click on the "Thank" icon.
Contact me about long distance tutoring!

Thanked by: finance
Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now.
GmatKiss GMAT Titan
Joined
26 Jul 2011
Posted:
2790 messages
Followed by:
41 members
Thanked:
205 times
Target GMAT Score:
700+
GMAT Score:
640
Sat May 19, 2012 12:24 pm
GMATGuruNY wrote:
finance wrote:
Two cars A and B start from Boston and New York respectively simultaneously and travel towards each other at constant speeds along the same route. After meeting at a point between Boston and New York the two cars A and B proceed to their respective destinations of New York and Boston. Car A reaches New York 40 minutes after the two cars have met and Car B reaches Boston 90 minutes after they have met. How long did Car A take to cover the distance between Boston and New York?

A. 1 hour

B. 1 hour 10 minutes

C. 2 hours 30 minutes

D. 1 hour 40 minutes

E. 2 hours 10 minutes
We can plug in the answers, which represent the time for A to travel the entire distance.

We should start with the median amount of time, 1 hour + 40 minutes.

Answer choice D: Total time for A = 100 minutes.
Since A travels for 40 minutes after A and B meet, time for A and B to meet = 100-40 = 60 minutes.
Since B travels for 90 minutes after A and B meet, total time for B = 60+90 = 150 minutes.
Let distance = 300 miles.
Rate for A = d/t = 300/100 = 3 miles per minute.
Rate for B = d/t = 300/150 = 2 miles per minute.
When elements work together to cover a distance, we add their rates.
Combined rate for A and B = 3+2 = 5 miles per minute.
Time for A and B to meet = d/r = 300/5 = 60 minutes. Success!

Hi,

How can we assume it to be 300?
Also can someone please explain how the same assumption will not lead us to the result if we choose some other option to deal with in the first place.

TIA,
GK

### Best Conversation Starters

1 varun289 43 topics
2 greenwich 30 topics
3 sana.noor 21 topics
4 guerrero 20 topics
5 killerdrummer 19 topics
See More Top Beat The GMAT Members...

### Most Active Experts

1 Brent@GMATPrepNow

GMAT Prep Now Teacher

202 posts
2 GMATGuruNY

The Princeton Review Teacher

143 posts
3 Anju@Gurome

Gurome

134 posts
4 Jim@StratusPrep

Stratus Prep

86 posts
5 David@VeritasPrep

Veritas Prep

41 posts
See More Top Beat The GMAT Experts