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by MBA.Aspirant » Sun Jun 05, 2011 12:27 am
If
(x + 5)/y
is a prime integer, which of the following must be true?
I. y = 5x
II. y is a prime integer.
III.(x + 5)/y is odd.
(A) None
(B) I only
(C) II only
(D) I and II only
(E) II and III only
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by Anurag@Gurome » Sun Jun 05, 2011 1:01 am
MBA.Aspirant wrote:If (x + 5)/y is a prime integer, which of the following must be true?
I. y = 5x
II. y is a prime integer.
III.(x + 5)/y is odd.
Let x = 3 and y = 4, then (x + 5)/y = (3 + 5)/4 = 2 --> A prime integer

But neither y = 5x nor y is prime integer nor (x + 5)/y is odd.
Hence, all of them are false.

The correct answer is A.
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by cans » Sun Jun 05, 2011 1:11 am
(x+5)/y is prime
a)y=5x. not true. (x=4,y=3)
b)y is prime. not true. x=3,y=4
c)(x+5)/y is odd. not true. x=3,y=4
IMO A
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by MBA.Aspirant » Sun Jun 05, 2011 5:47 am
Thanks Dr. Anurag
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by sunilramu » Sun Jun 05, 2011 8:30 am
(x + 5)/y
is a prime integer, which of the following must be true?
I. y = 5x
II. y is a prime integer.
III.(x + 5)/y is odd.

(x+5) = y.P where P is a prime.
Select values for x and y such that P is 2
(x+5)=2y
y=1 => x=-3 will negate I, II and III

IMO A
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by Ahmed MS » Sun Jun 05, 2011 8:57 am
I am wondering if we take the value of x=4, and value of y=3, then option ii and iii will be right. As (x+5)/y, will be the prime integer.

So, (4+5)/3 = 9/3 = 3


Pardon me if I am wrong.


Cheers.
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by cans » Sun Jun 05, 2011 9:24 am
Ahmed MS wrote:I am wondering if we take the value of x=4, and value of y=3, then option ii and iii will be right. As (x+5)/y, will be the prime integer.

So, (4+5)/3 = 9/3 = 3


Pardon me if I am wrong.


Cheers.
If
(x + 5)/y
is a prime integer, which of the following must be true?
Question says must be true. Thus it should be true for all values of x and y. and not just one pair.
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Cans!!
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by sandeep800 » Sun Jun 05, 2011 10:30 am
A is correct...
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by MBA.Aspirant » Mon Jun 06, 2011 5:27 am
cans wrote:
Ahmed MS wrote:I am wondering if we take the value of x=4, and value of y=3, then option ii and iii will be right. As (x+5)/y, will be the prime integer.

So, (4+5)/3 = 9/3 = 3


Pardon me if I am wrong.


Cheers.
If
(x + 5)/y
is a prime integer, which of the following must be true?
Question says must be true. Thus it should be true for all values of x and y. and not just one pair.
@ Cans: when x=4 y =3, II and III will be true

x+5/y = 4+5/3 = 3 <= prime integer

II) y is a prime integer.
III.(x + 5)/y is odd.

??
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by cans » Mon Jun 06, 2011 6:24 am
MBA.Aspirant wrote:
cans wrote:
Ahmed MS wrote:I am wondering if we take the value of x=4, and value of y=3, then option ii and iii will be right. As (x+5)/y, will be the prime integer.

So, (4+5)/3 = 9/3 = 3


Pardon me if I am wrong.


Cheers.
If
(x + 5)/y
is a prime integer, which of the following must be true?
Question says must be true. Thus it should be true for all values of x and y. and not just one pair.
@ Cans: when x=4 y =3, II and III will be true

x+5/y = 4+5/3 = 3 <= prime integer

II) y is a prime integer.
III.(x + 5)/y is odd.

??
Yeah when x=4,y=3 II and III will be true.
But the question says
which of the following must be true?
Thus they ought to be true for all value of x and y and not just for x=4,y=3.
Say x=1,y=1, y is not prime and (x+5)/y is not odd. Thus we choose 'A'. None
If my post helped you- let me know by pushing the thanks button ;)

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Cans!!
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