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Can you explain this question for me??

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by juyau800 » Mon Dec 22, 2008 1:49 am
If n and y are positive integers and 450y = n^3

Which of the following is an integer?

I. y / 3 x 2^2 x 5

II. y / 3^2 x 2 x 5

III. y / 3 x 2 x 3^2

A. I
B. II
C. III
D. I and II
E. I and II and III

I don't understand how to crack this. Can someone explain? thanks!
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by vishubn » Mon Dec 22, 2008 1:53 am
https://www.beatthegmat.com/450y-how-to- ... 12088.html

u can follow this link !!

if still doubtfull.. i guess we can all pitch in

vishu
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by vishubn » Mon Dec 22, 2008 2:04 am
Yes one general approach ! to this ! try bring the values on right hand side and left hand side on the same page !!

So all u can think abt when i say that is factorisation :)

sooo 450--- factors !!

y u have few factors equated to bring all the prime factors on powers of 3 to get a cube root of a number !

So B is the only one which satisfies the solutuon ... " must be true" other options might be or might not be ! situtation

HTH

vishi
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by ronniecoleman » Mon Dec 22, 2008 2:08 am
If n and y are positive integers and 450y = n^3

Which of the following is an integer?

I. y / 3 x 2^2 x 5

II. y / 3^2 x 2 x 5

III. y / 3 x 2 x 3^2

let me try:

45 * 10 * y = n3
5*5*3*3*2* y = n3

now for n to be integer

y can be 5*3*2*2

or multiples:

My take is E


SORRY It has to A

it says must be a integer...
and the options i considered can be or cannot be...
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by vishubn » Mon Dec 22, 2008 2:23 am
OA B

vishu
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by amitabhprasad » Mon Dec 22, 2008 10:11 am
The OA should be "A"
If you are looking at the link, it contain 'A" as NONE
and "B" as the correct value
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Re: Can you explain this question for me??

by vin25 » Mon Dec 22, 2008 1:07 pm
juyau800 wrote:If n and y are positive integers and 450y = n^3

Which of the following is an integer?

I. y / 3 x 2^2 x 5

II. y / 3^2 x 2 x 5

III. y / 3 x 2 x 3^2

A. I
B. II
C. III
D. I and II
E. I and II and III

I don't understand how to crack this. Can someone explain? thanks!
450=2*3^2*5^2 => we need one 3, two 2s and one 5 => option A is the correct choice.
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by LizinCali » Mon Dec 22, 2008 3:05 pm
I've read both posts and still don't understand where the 2, 2, 3, 5, N = Y came from.

Thanks for your help! :oops:
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by LizinCali » Mon Dec 22, 2008 3:13 pm
I've read both posts and still don't understand where the 2, 2, 3, 5, N = Y came from.

Thanks for your help! :oops:
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by umaa » Mon Dec 22, 2008 9:06 pm
450y = n ^ 3

y = (n ^ 3)/450

n and y both are integer. So, we should find the number n which is still an integer after getting divided by 450.

n = 30 will satisfy the condition.

So, If you apply n= 30 in the quation, you'll get y = 60.

Apply that in all the three answers.

Only the first answer satisfies the condition.

Hope this helps..
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