If x and y are positive, is 3x > 7y?

[mitzwillrockgmat]

If x and y are positive, is 3x > 7y?

(1) x > y + 4

(2) -5x < -14y

I've seen alot of posts regarding this question but all are very confusing as some say answer is B while others D.

The answer provided is D though.

When i did this question in a practice test, i picked B but now knowing the answer, I tried working backwards.

Can anyone shed light on what the correct answer actually is & how to approach this question?


This is what I did:

1) I don't get it !

2) -5x<-14y

so x > -14y/-5

x > 2.8y

so 3x > 8.4y hence, 3x >7y

so stat sufficient

[outreach]

Q is x>2.3y?

option 1

if y=1 then X>5
this satisfies Q
if y=-1 then x>4
this satisfies Q

hence A can be correct

option 2 u have already proved

hence D

If x and y are positive, is 3x > 7y?

(1) x > y + 4

(2) -5x < -14y

I've seen alot of posts regarding this question but all are very confusing as some say answer is B while others D.

The answer provided is D though.

When i did this question in a practice test, i picked B but now knowing the answer, I tried working backwards.

Can anyone shed light on what the correct answer actually is & how to approach this question?


This is what I did:

1) I don't get it !

2) -5x<-14y

so x > -14y/-5

x > 2.8y

so 3x > 8.4y hence, 3x >7y

so stat sufficient

[mitzwillrockgmat]

Q is x>2.3y?

option 1

if y=1 then X>5
this satisfies Q
if y=-1 then x>4 *****value of x & y is positive

this satisfies Q

hence A can be correct

option 2 u have already proved

hence D

If x and y are positive, is 3x > 7y?

(1) x > y + 4

(2) -5x < -14y

I've seen alot of posts regarding this question but all are very confusing as some say answer is B while others D.

The answer provided is D though.

When i did this question in a practice test, i picked B but now knowing the answer, I tried working backwards.

Can anyone shed light on what the correct answer actually is & how to approach this question?


This is what I did:

1) I don't get it !

2) -5x<-14y

so x > -14y/-5

x > 2.8y

so 3x > 8.4y hence, 3x >7y

so stat sufficient

Hi, the question mentions that the value of x & y is positive so your second set of values are not correct. can show me some other values maybe which prove that the stat is sufficient?

Also, shed some light on why you decided to pick those plug in values?

[Stuart@KaplanGMAT]

If x and y are positive, is 3x > 7y?

(1) x > y + 4

(2) -5x < -14y

We know that x and y are positive, so we can rephrase the question as:

is x/y > 7/3?

(1) x > y + 4

let's start by picking very small values: y=1 and x=6 (we could pick smaller values if we wanted, since we don't have to pick integers):

Is 6/1 > 7/3? YES

now let's try really big values:

y = 95, x=100

is 100/95 > 7/3? NO

accordingly, (1) is not sufficient alone.

[mitzwillrockgmat]

If x and y are positive, is 3x > 7y?

(1) x > y + 4

(2) -5x < -14y

We know that x and y are positive, so we can rephrase the question as:

is x/y > 7/3?

(1) x > y + 4

let's start by picking very small values: y=1 and x=6 (we could pick smaller values if we wanted, since we don't have to pick integers):

Is 6/1 > 7/3? YES

now let's try really big values:

y = 95, x=100

is 100/95 > 7/3? NO

accordingly, (1) is not sufficient alone.

OKay, so the trick here is to use extreme plug in values to see if the statement is sufficient or not. Thank you!

[GShahin]

I didn get one thing, so what is the answer in here is it B?