NEW HERE? LEARN MORE
closeclose
Last visit was: 25 Apr 2024, 06:11 It is currently 25 Apr 2024, 06:11
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

A race car driver has to drive from the intersection A to in

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
bblast
Manager
Manager
Joined: 25 Dec 2010
Affiliations: The Earth organization, India
Posts: 150
Own Kudos [?]: 31 [3]
Given Kudos: 12
Concentration: Operations
 Q47  V34 GMAT 2: 680  Q48  V35 GMAT 3: 710  Q48  V38
GPA: 3.3
WE 1: SAP consultant-IT 2 years
WE 2: Entrepreneur-family business 2 years
Send PM
A race car driver has to drive from the intersection A to in [#permalink] New post   03 Jun 2011, 09:23
3
Bookmarks
00:00
A
B
C
D
E

Difficulty:

65% (hard)

Question Stats:

44% (01:35) correct 56% (01:56) wrong based on 52 sessions
Hide Show timer Statistics

A race car driver has to drive from the intersection A to intersection B along the route that is confined to the square grid of four touchstones and three avenues shown in the map above. How many routes from A to B can the racer take that have minimum possible length?

A. 7
B. 9
C. 10
D. 14
E. 18


Show Spoiler
https://s3.amazonaws.com/production.grockit.com/content_images/production/1264222415/40_a.jpg

cant we solve this by combinatorics ? grockit gives solution via counting which is cumbersome.

Attachment:
40_a.jpg
40_a.jpg [ 9.39 KiB | Viewed 1370 times ]
ShowHide Answer
Official Answer
C
User avatar
bhandariavi
Manager
Manager
Joined: 04 Apr 2010
Posts: 91
Own Kudos [?]: 608 [2]
Given Kudos: 31
Send PM
Re: A race car driver has to drive from the intersection A to in [#permalink] New post   03 Jun 2011, 09:51
2
Kudos
UUULL (shortest possible way includes 3 UPs and 2 Lefts)
No. of arrangement includes = 5! / (3! * 2!) = 10
C is the quick answer.
User avatar
fluke
Retired Moderator
Joined: 20 Dec 2010
Posts: 1114
Own Kudos [?]: 4702 [0]
Given Kudos: 376
Send PM
Re: A race car driver has to drive from the intersection A to in [#permalink] New post   03 Jun 2011, 09:37
bblast wrote:
A race car driver has to drive from the intersection A to intersection B along the route that is confined to the square grid of four touchstones and three avenues shown in the map above. How many routes from A to B can the racer take that have minimum possible length?

7
9
10
14
18

https://s3.amazonaws.com/production.grockit.com/content_images/production/1264222415/40_a.jpg

cant we solve this by combinatorics ? grockit gives solution via counting which is cumbersome.


Count the number of columns, say c
Count the number of rows, say r

\(Ways = C^{(c+r)}_{c}\)
OR
\(Ways = C^{(c+r)}_{r}\)

In this figure,
c=2
r=3
c+r=5
\(Ways = C^{5}_{3} = 10\)

Ans: "C"
**************************************************
User avatar
bumpbot
Non-Human User
Joined: 09 Sep 2013
Posts: 32668
Own Kudos [?]: 821 [0]
Given Kudos: 0
Send PM
Re: A race car driver has to drive from the intersection A to in [#permalink] New post   11 Apr 2019, 10:59
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 Club Bot
gmatclubot
Re: A race car driver has to drive from the intersection A to in [#permalink]
11 Apr 2019, 10:59
Moderators:
Bunuel
Math Expert
92912 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions