and a second wheel

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by Lifetron » Wed Aug 08, 2012 12:35 am
E !

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by rajeshsinghgmat » Thu Mar 14, 2013 12:19 am
E in answer.

2*pi*(x/2)=pi*x

(pi*x)*(100)=d

(pi*y)*n=d

n=100*(x/y)

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by jaspreetsra » Tue Nov 25, 2014 12:10 am
A wheel has a diameter of x inches and a second wheel has a diameter of y inches. The first wheel covers a distance of d feet in 100 revolutions. How many revolutions does the second wheel make in covering d feet?

(A) 100xy
(B) 100y - x
(C) 100x - y
(D) 100y/x
(E) 100x/y

Ans: D?

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by GMATinsight » Tue Nov 25, 2014 3:34 am
jaspreetsra wrote:A wheel has a diameter of x inches and a second wheel has a diameter of y inches. The first wheel covers a distance of d feet in 100 revolutions. How many revolutions does the second wheel make in covering d feet?

(A) 100xy
(B) 100y - x
(C) 100x - y
(D) 100y/x
(E) 100x/y

Ans: D?
1 Rev of First wheel = 1 Circumference of Wheel = Pi x
1 Rev of Second wheel = 1 Circumference of Wheel = Pi y

No. of Revolution x Distance traveled in 1 Rev = Total Distance Traveled

No. of Revolution of Second Wheel = d / Pi y

But The first wheel covers a distance of d feet in 100 revolutions
i.e. d = 100 Pi x


Therefore,
No. of Revolution of Second Wheel = d / Pi y = 100 pi x / Pi y = 100 x / y

Answer: Option E
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by nikhilgmat31 » Mon Jul 27, 2015 9:45 pm
Answer is E.

Distance Travelled = Circumference of wheel * Number of revolutions of wheel.

pie * x * 100 = d = pie * y * r
r = 100x/y

E