is X>Y? (1) x=y+2 (2) x/2=y-1

[Setarehrrr]

Can someone help me the answer is A but I thought it is D because I would get a bigger number for X if I plug it in...

Thank you

[[email protected]]

Hi Setarhrrr,

You seem comfortable with the idea that Fact 1 is SUFFICIENT (since X = Y + 2, but definition X would have to be bigger than Y). With Fact 2, you can TEST VALUES, but you have to be thorough with your thinking...

2) X/2 = Y - 1

IF....
X = 4 and Y = 3, then the answer to the question is YES.
X = 2 and Y = 2, then the answer to the question is NO.
Fact 2 is INSUFFICIENT

GMAT assassins aren't born, they're made,
Rich

[Brent@GMATPrepNow]

Is x > y?

1) x = y + 2
2) x/2 = y - 1

Target question: Is x > y?

Statement 1: x = y + 2
Since this tells us that x and y+2 are equal, let's take the target question, and replace x with y + 2 to get: Is y + 2 > y?
The answer is a resounding YES!! y + 2 is TWO GREATER THAN y
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: x/2 = y - 1
To get a better idea of what this equation is telling us, let's eliminate the fraction by multiplying both sides by 2.
We get: x = 2y - 2
There are several values of x and y that satisfy statement 2. Here are two:
Case a: x = 4 and y = 3. In this case x > y
Case b: x = 0 and y = 1. In this case x < y
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer: A

Cheers,
Brent

[Setarehrrr]

Is x > y?

1) x = y + 2
2) x/2 = y - 1

Target question: Is x > y?

Statement 1: x = y + 2
Since this tells us that x and y+2 are equal, let's take the target question, and replace x with y + 2 to get: Is y + 2 > y?
The answer is a resounding YES!! y + 2 is TWO GREATER THAN y
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: x/2 = y - 1
To get a better idea of what this equation is telling us, let's eliminate the fraction by multiplying both sides by 2.
We get: x = 2y - 2
There are several values of x and y that satisfy statement 2. Here are two:
Case a: x = 4 and y = 3. In this case x > y
Case b: x = 0 and y = 1. In this case x < y
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer: A

Cheers,
Brent

Thank you for your response,
I think what confused me for (2) is that it is saying x is equal to 2*Y minus two, so if x=6 than y=3 than subtract 2.... so x will always be bigger. For statement (1) I get that x is equal to Y and add 2, so I tried to approach (2) the same way... if you get my logic...

[Setarehrrr]

Is x > y?

1) x = y + 2
2) x/2 = y - 1

Target question: Is x > y?

Statement 1: x = y + 2
Since this tells us that x and y+2 are equal, let's take the target question, and replace x with y + 2 to get: Is y + 2 > y?
The answer is a resounding YES!! y + 2 is TWO GREATER THAN y
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: x/2 = y - 1
To get a better idea of what this equation is telling us, let's eliminate the fraction by multiplying both sides by 2.
We get: x = 2y - 2
There are several values of x and y that satisfy statement 2. Here are two:
Case a: x = 4 and y = 3. In this case x > y
Case b: x = 0 and y = 1. In this case x < y
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer: A

Cheers,
Brent

Thank you for your response,
I think what confused me for (2) is that it is saying x is equal to 2*Y minus two, so if x=6 than y=3 than subtract 2.... so x will always be bigger. For statement (1) I get that x is equal to Y and add 2, so I tried to approach (2) the same way... if you get my logic...

[Setarehrrr]

Hi Setarhrrr,

You seem comfortable with the idea that Fact 1 is SUFFICIENT (since X = Y + 2, but definition X would have to be bigger than Y). With Fact 2, you can TEST VALUES, but you have to be thorough with your thinking...

2) X/2 = Y - 1

IF....
X = 4 and Y = 3, then the answer to the question is YES.
X = 2 and Y = 2, then the answer to the question is NO.
Fact 2 is INSUFFICIENT

GMAT assassins aren't born, they're made,
Rich

Thank you for your response,
I think what confused me for (2) is that it is saying x is equal to 2*Y minus two, so if x=6 than y=3 than subtract 2.... so x will always be bigger. For statement (1) I get that x is equal to Y and add 2, so I tried to approach (2) the same way... if you get my logic...

[Brent@GMATPrepNow]

[for statement 2] if x=6 than y=3 than subtract 2.... so x will always be bigger.

Be careful. You aren't looking at the entire equation.
The given equation is: x/2 = y - 1

As you can see, x = 6 and y = 3 is not a solution to this equation.
If we plug x = 6 and y = 3 into the given equation, we get: 6/2 = 3 - 1
Simplify to get: 3 = 3 - 1. Doesn't work.

You are using a different kind of technique.

I should also note that halving a number (dividing by 2) does not always make that number smaller (as you suggested).
Yes, if we take 6 and halve it, we get 3, and 3 IS less than 6.
However, if we take -10 and halve it, we get -5, and -5 is NOT less than -10.

Does that help?

Cheers,
Brent

[Jay@ManhattanReview]

Can someone help me the answer is A but I thought it is D because I would get a bigger number for X if I plug it in...

Thank you

A similar problem is discussed here.

https://www.beatthegmat.com/if-x-2-y-2-i ... tml#791483

Relevant book: Manhattan Review GMAT Math Essentials Guide

Jay
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Manhattan Review GMAT Prep

Locations: Almaty | Minsk | Aarhus | Vilnius | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.

[Mannit]

Is x > y?

1) x = y + 2
2) x/2 = y - 1

Target question: Is x > y?

Statement 1: x = y + 2
Since this tells us that x and y+2 are equal, let's take the target question, and replace x with y + 2 to get: Is y + 2 > y?
The answer is a resounding YES!! y + 2 is TWO GREATER THAN y
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: x/2 = y - 1
To get a better idea of what this equation is telling us, let's eliminate the fraction by multiplying both sides by 2.
We get: x = 2y - 2
There are several values of x and y that satisfy statement 2. Here are two:
Case a: x = 4 and y = 3. In this case x > y
Case b: x = 0 and y = 1. In this case x < y
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer: A

Cheers,
Brent

We need to consider that x can take up negative value as well. Let say x = -3, y = -1 In this case x<y
if x=5 then y=3 i.e x>y thus statement 1 is insufficient.
Statement II
Statement 2 is insufficient as
Case a: x = 4 and y = 3.
Case b: x = 0 and y = 1.
ON using both the statements together
x=y+2
x/2=y-1

we get the value of y=4 and that of x= 6 in which x>y
thus C should be the correct answer.

Regards
Mannit

[Brent@GMATPrepNow]

Is x > y?

1) x = y + 2
2) x/2 = y - 1

Target question: Is x > y?

We need to consider that x can take up negative value as well. Let say x = -3, y = -1 In this case x<y
if x=5 then y=3 i.e x>y thus statement 1 is insufficient.

x = -3, y = -1 is not a solution to the equation x = y + 2
If we plug x = -3 and y = -1 into the equation we get: -3 = -1 + 2
Evaluate to get: -3 = 1
Doesn't work.

Cheers,
Brent