y ≠ 3

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y ≠ 3

by shibal » Thu Jul 16, 2009 4:19 am
If y ≠ 3 and 2x/y is a prime integer greater than 2, which of the following must be true?
I. x = y
II. y = 1
III. x and y are prime integers.

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by raghavsarathy » Sat Jul 18, 2009 2:07 am
Statement I
If x=y then 2x/y reduces to 2. But the condition is that the result is a prime number reater than 2. Hence statement 1 is false

Statement 2

If y =1 then the result of the eqn is 2x. Since we need a prime number greater than 2 , we need to have values of x greater than 1. Each of these will give us an even number greater than 2. Even numbers greater than 2 are not prime . Hence 2 is false

Statement 3
To prove this statment wrong we need to show that non-prime values of x and y can also give the required result

let x= 6 and y= 4. 2x/y gives 3. Hence statement 3 is also wrong.

Ans- None of these