A circular rim 28 inches in diameter rotates the same number : PS Archive
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 23 Jan 2017, 11:49

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# A circular rim 28 inches in diameter rotates the same number

Author Message
Manager
Joined: 30 Jan 2006
Posts: 145
Followers: 1

Kudos [?]: 27 [0], given: 0

A circular rim 28 inches in diameter rotates the same number [#permalink]

### Show Tags

15 Apr 2006, 19:59
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

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

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 x revolutions per second, how many revolutions per minute does the larger rim make in terms of x?
Manager
Joined: 09 Feb 2006
Posts: 129
Location: New York, NY
Followers: 1

Kudos [?]: 7 [0], given: 0

### Show Tags

16 Apr 2006, 05:15
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 x revolutions per second, how many revolutions per minute does the larger rim make in terms of x?

This is a ratio problem. If they move the same number of inches, then the smaller rim is moving a bit faster. if they move 7 inches in a second, then that is a 1/4 turn for the smaller rim, and 1/5 of a turn for the larger rim. Armed with this, we can work out a ratio for their turning. Let's set x as 1/4; The larger rim will make 12 revolutions in a minute. Therefore, in terms of x, the larger rim will turn 48x.
Intern
Joined: 04 May 2004
Posts: 48
Location: India
Followers: 0

Kudos [?]: 28 [0], given: 0

### Show Tags

16 Apr 2006, 06:44
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 x revolutions per second, how many revolutions per minute does the larger rim make in terms of x?

I dont know about solution posted by jcgoodchild but if I was to face this question, I would use ratios to solve the question. the ratio of radii is 4/5 and the answer should be a multiple of 4/5 ... I might be wrong. I would really like to have opinion of other people on use of ratios.
_________________
16 Apr 2006, 06:44
Display posts from previous: Sort by