what is y in terms of x

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what is y in terms of x

by rerika01 » Tue Jul 05, 2011 6:59 pm
If the speed of x meters per second is equivalent to the speed of y kilometers per hour, what is "y" in terms of "x"?

a) 5x/18
b) 6x/5
c) 18x/5
d) 60x
e) 3,600,000x

What is the easiest way to tackle something like this?

Thanks!
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by abhisays » Tue Jul 05, 2011 7:21 pm
It's very simple. Always remember, to convert m/s to km/h we need to multiply by 18/5.

so x m/s will be x * 18/5 km/h

now since units are equal we can write

x * 18/5 = y

therefore, y = 18x/5

Hence, answer is C

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by GMATGuruNY » Tue Jul 05, 2011 8:38 pm
rerika01 wrote:If the speed of x meters per second is equivalent to the speed of y kilometers per hour, what is "y" in terms of "x"?

a) 5x/18
b) 6x/5
c) 18x/5
d) 60x
e) 3,600,000x

What is the easiest way to tackle something like this?

Thanks!
We can plug in values.

Let x=5 meters per second.
Over 1 minute, 60*5 = 300 meters are travelled.
Over 1 hour, 60*300 = 18,000 meters are travelled.
Since 18,000 meters = 18 kilometers, y=18. This is our target.

Now we plug x=5 into the answers to see which yields our target of 18.

Only answer choice C works:
18x/5 = (18*5)/5 = 18.

The correct answer is C.
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by Anurag@Gurome » Tue Jul 05, 2011 9:26 pm
rerika01 wrote:If the speed of x meters per second is equivalent to the speed of y kilometers per hour, what is "y" in terms of "x"?
x (meters/second) = y (kilometers/hour) = y (1000 meters/3600 seconds) = (5/18)*y (meters/second)

Therefore, (5/18)*y = x --> y = (18x/5)

The correct answer is C.
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by MBA.Aspirant » Tue Jul 05, 2011 10:13 pm
rerika01 wrote:If the speed of x meters per second is equivalent to the speed of y kilometers per hour, what is "y" in terms of "x"?

a) 5x/18
b) 6x/5
c) 18x/5
d) 60x
e) 3,600,000x

What is the easiest way to tackle something like this?

Thanks!
x:1
1000y:3600

1000y = 3600x
y= 18/5x