BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

PS Ratio Problem

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 28
Joined: Fri Dec 14, 2007 7:58 am
Thanked: 1 times
by Riggz » Sat Mar 01, 2008 9:44 pm
The ratio of buses to cars on River Road is 2 to 23. If there are 630 fewer buses than cars on River Road, how many cars are on River Road?

a)30
b)60
c)660
d)690
e)750

Can someone pls explain this one to me? Explanation is not clear to me.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
Newbie | Next Rank: 10 Posts
Posts: 3
Joined: Sat Mar 01, 2008 9:19 pm

by iwillmakeit » Sat Mar 01, 2008 9:55 pm
B/C = 2/23

B = C - 630

Solve both to arrive at the answer.

(C-630)/C = 2/23

1 - 630/C = 2/23

230/C = 21/23

C = 630*23/21 = 690
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Newbie | Next Rank: 10 Posts
Posts: 1
Joined: Tue Oct 09, 2007 10:05 pm
Location: Jakarta, Indonesia

by yozero » Sun Mar 02, 2008 3:22 am
well, i think the answer should be "B"

2(x)+630=23(x)
21(x)=630
x=30

since the ratio of bushes to car is 2(x):23 (x)
then the number of bushes is 2(30) = 60
YOZERO
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 28
Joined: Fri Dec 14, 2007 7:58 am
Thanked: 1 times

by Riggz » Sun Mar 02, 2008 8:05 am
correct answer is D 690. thanks iwillmakeit

explanation didnt show the two equations.

yozero u are almost correct lol. It asks for number of cars not buses. But can you please explain how you dervied the equation 2x + 630 = 23x? This is how mgmat has the explanation as well.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Newbie | Next Rank: 10 Posts
Posts: 1
Joined: Wed Feb 06, 2008 11:17 am

by dgmat » Wed Mar 12, 2008 2:07 pm
Okay this is how I see it.

Cars (C), Buses (B)

B = C - 630 (Buses 630 less than car)

=> 2/23 = B/C or 2/23 = (C - 630) / C
=> 2C = 23C - 14490
=> C= 14490/21
=> C= 690
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 72
Joined: Mon Mar 10, 2008 10:29 am
Thanked: 25 times

by tmmyc » Wed Mar 12, 2008 4:32 pm
Riggz wrote:But can you please explain how you dervied the equation 2x + 630 = 23x? This is how mgmat has the explanation as well.
The question states that the ratio of buses to cars is 2 to 23.

This means there might be 2 buses and 23 cars,
or 4 buses and 46 cars,
or 6 buses and 69 cars,
etc.

Hence, there are
2(x) buses and 23(x) cars
where x is some positive integer.

Next, the question states there are 630 fewer buses than cars. This means the number of buses plus 630 will equal the number of cars.

We already know the number of buses from the previous statement: 2(x)
We also know the number of cars: 23(x)

Translating all the statements into one mathematical equation gives you

2(x) + 630 = 23(x)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 39
Joined: Sun Apr 13, 2008 12:17 am

by yalephd2007 » Sun Apr 13, 2008 9:04 am
The answer is D.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 36
Joined: Tue Oct 02, 2007 10:25 am
Thanked: 2 times

by dalwow » Wed Apr 16, 2008 12:48 pm
Maybe this is overkill for this problem, but I worked this out in a way that seemed quite simple. The difference from cars/buses is 21. The total difference is 630. 630/21 =30. This is the number of buses. Multiply 30*23(which is the number of cars vs. the 30 buses we know we have) and we get 690. To me this looks like an easy way to work it out. Please point it out if I'm wrong, thanks.
Still Learning
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 631
Joined: Mon Feb 18, 2008 11:57 pmFollowed by: 3 members
Thanked: 29 times

by netigen » Wed Apr 16, 2008 1:04 pm
dalwow wrote:Maybe this is overkill for this problem, but I worked this out in a way that seemed quite simple. The difference from cars/buses is 21. The total difference is 630. 630/21 =30. This is the number of buses. Multiply 30*23(which is the number of cars vs. the 30 buses we know we have) and we get 690. To me this looks like an easy way to work it out. Please point it out if I'm wrong, thanks.
You are not doing anything wrong but just solving the following two equations:

Bus/Car = 2/23
Car = Bus+630

if you solve these two, you get Car = 23 * 30
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 36
Joined: Tue Oct 02, 2007 10:25 am
Thanked: 2 times

by dalwow » Thu Apr 17, 2008 5:12 am
Thanks
Still Learning
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1