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 350,000 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:

A circular rim 28 inches in diameter rotates the same number [#permalink]
09 Dec 2007, 10:21

A circular rim 28 inches in diameter rotates the same number of inches
per second as a circular rim 35 inches in diameter. If the smaller
rim makes y revolutions per second, hom many revolution per minute
does the larger rim make in terms of y
------------------------------------------------------------------------

The ratio of two quantities is 3 to 4. If each of the quantities is
increased by 5, what is the ratio of these two new quantities

The addition problem above shows four of the 24 different integers that can
be formed by using each of the digits 1, 2, 3 and 4 exactly once in each
integer. What is the sum of these 24 integers

First problem:
First let's find the number of inches the small and large rim rotate in one revolution - it is circumference length or:
smaller rim: 2piR=28pi (which is around 84 but we won't need this number).
larger rim: 2piR=35pi
Let x be number of revolutions per minte the larger rim makes => x/60 - number of revolutions per second.
If a smaller rim makes y revolutions per second then it rotates 28pi*y number of inches per second which equals number of inches per second of larger rim or 35pi*x/60. Solve it for x:
28piy=36pix/60 => 36x=1680y => x=140/3*y
That's what I got... strange answer. I wonder if it is in the answer choices?

Second problem:
To my mind it's impossible to tell what will be the ratio of new quantities. If we take different numbers with the given ratio and check them the new ratios will be different:
1) If we take 3 and 4. 3+5=8, 4+5=9, so the ratio is 8/9.
2) If we take 6 and 8. 6+5=11, 8+5=13, so the ratio is 11/13
We get two different ratios, so we can't say for sure what will be the answer.

Third:
If m is an integer, is m odd?
1) m/2 is not an even integer
2) m-3 is an even integer

I would say B
(i) can't say m=6 and m=5 both don't have even m/2
(ii) m-3=even => m=even +3=> m=odd
================================
Fourth:
1234
1243
....
....
+4321

24 permutations means that on the ones we will have 6x1's, 6x2's,6x3's,6x4's
6+12+18+24=60
same on the tens, hundredths and thousands
so 60+600+6000+60000=66660
=================================
where did you get these questions from

Re: I need help with these problems [#permalink]
10 Dec 2007, 09:27

gmat2006-8001 wrote:

A circular rim 28 inches in diameter rotates the same number of inches per second as a circular rim 35 inches in diameter. If the smaller rim makes y revolutions per second, hom many revolution per minute does the larger rim make in terms of y ------------------------------------------------------------------------

Getting 48y.

For smaller rim, 1 rev = 28pi inches
If it makes y revs/second then it cover 28*pi*y inches/second
Since speed of big rim = speed of small rim, big rim also covers 28*pi*y inches/second
Since for the big rim, 1 rev = 35pi inches, 28*pi*y inches = 28*pi*y/35*pi = 28y/35 revs
Since the big rim takes 28y/35 revs in 1 sec, it will make 28y/35*60 = 48 y revs in 1 min.

Re: I need help with these problems [#permalink]
10 Dec 2007, 09:38

gmat2006-8001 wrote:

1234 1243 .... .... +4321 ------

The addition problem above shows four of the 24 different integers that can be formed by using each of the digits 1, 2, 3 and 4 exactly once in each integer. What is the sum of these 24 integers

Re: I need help with these problems [#permalink]
10 Dec 2007, 23:48

GK_Gmat wrote:

gmat2006-8001 wrote:

1234 1243 .... .... +4321 ------

The addition problem above shows four of the 24 different integers that can be formed by using each of the digits 1, 2, 3 and 4 exactly once in each integer. What is the sum of these 24 integers

Can someone explain how to solve this?

1, 2, 3, 4 and orders matter so all possibilities = 4! = 24

for each of the digitd, there are six 1s, six 2s, six 3s, and six 4s.
so sum = 66,660

24 permutations means that on the ones we will have 6x1's, 6x2's,6x3's,6x4's 6+12+18+24=60 same on the tens, hundredths and thousands so 60+600+6000+60000=66660 ================================= where did you get these questions from

Type of Visa: You will be applying for a Non-Immigrant F-1 (Student) US Visa. Applying for a Visa: Create an account on: https://cgifederal.secure.force.com/?language=Englishcountry=India Complete...

I started running back in 2005. I finally conquered what seemed impossible. Not sure when I would be able to do full marathon, but this will do for now...