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# ps - wheels (m05q23)

Author Message
Intern
Joined: 24 Jun 2010
Posts: 41

Kudos [?]: 6 [0], given: 3

Location: Toronto
Schools: Berkeley Haas, UCLA Anderson, NYU Stern
Re: ps - wheels (m05q23) [#permalink]

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28 Jul 2010, 12:17
Is there value in having 3 cogs?

Kudos [?]: 6 [0], given: 3

Intern
Joined: 29 Jan 2011
Posts: 9

Kudos [?]: [0], given: 2

Re: ps - wheels (m05q23) [#permalink]

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04 Jan 2012, 22:46
I solved this by proportionality.
Now since the larger wheel drives the smaller wheel, they should be directly proportional in activity...

hence,
60/r = 8/2

r = 15
d = 30.

thats it. simple. took me less than 30 s for this one.

S

Kudos [?]: [0], given: 2

Senior Manager
Joined: 21 Jan 2010
Posts: 329

Kudos [?]: 225 [0], given: 12

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13 Sep 2012, 18:15
A machine consisting of 3 connected wheels is mixing concrete. The engine is running at a speed of 60 rpm and the mixer is mixing at a rate of 8 rpm. If the radius of the smaller (drive) wheel is 2 inches, what is the diameter of the mixing wheel? The smaller wheel is driven directly by the engine.

12
15
25
30
32

I dont understand this question. I can't visualize this problem, can somebody help ?

Thanks

Kudos [?]: 225 [0], given: 12

Senior Manager
Joined: 11 May 2011
Posts: 355

Kudos [?]: 120 [0], given: 46

Location: US

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13 Sep 2012, 20:46
I too got confused in my first read but if you read carefully you actually dont need to worry about the 3 connected wheels.
Statement says -
Small wheel -> radius = 2 inch , small wheel speed = 60 rpm becasue the question says that the smaller wheel is driven directly by the engine.
Mixer wheel -> radius or diameter = ? , speed = 8rpm

Mixer wheel diameter = 2pi.2*60/8pi = 30inch.

Cheers!
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Kudos [?]: 120 [0], given: 46

Re: wheel   [#permalink] 13 Sep 2012, 20:46

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# ps - wheels (m05q23)

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