Question: Is 5-2x Greater than -1?

Comment on Is 5-2x Greater than -1?

Like the last video if x was negative wouldn't the target question be x<3 ora x>-3?
gmat-admin's picture

I'm not sure which video you're referring to. Can you be more specific?

But for the second statement, x could be less than 2, but x < 3 defines that x could be less than 3 which includes 2 also so how it's sufficient unless x ≤ 2?
gmat-admin's picture

Be careful. The rephrased target question (Is x < 3?) isn't telling us that x is less than 3; it's asking us a question: "Is x < 3?"

We don't know whether x < 3. In fact, that's the target question we're trying to answer.

Statement 2 tells us that x < 2
Does this information help us determine whether or not x < 3?
Yes.
If it is the case x < 2, then we can be certain that x < 3

Does that help?

Cheers,
Brent

I got it. thankyou :)

But the questions is "Is X<3?", and second statement tells x<2, what if value of x is in between 2&3. Stmt 2 cannot tell it with certainty.
gmat-admin's picture

Be careful. The rephrased target question (Is x < 3?) isn't telling us that x is less than 3, greater than 3, or equal to 3.
It's just asking us the question "Is x < 3?"
We don't know whether x < 3. In fact, that's the target question we're trying to answer.

Statements, on the other hand, are TRUE pieces of information that may or may not help us answer the target question with certainty.
Statement 2 tells us that x < 2
Since we can be certain that x < 2, we can also be certain that the value of x can't be between 2 & 3.

More importantly, if x < 2, then we can be certain that x < 3
In other words, if x < 2, we can answer the rephrased target question with certainty: "YES, x is definitely less than 3."

Does that help?

Cheers,
Brent

Hi Brent,
Thanks for the great videos.
Was just wondering, do you suggest drawing number lines when solving certain inequality questions on the actual GMAT? Or do you use them in the videos just because it's easier for the viewer to understand? Thanks!
gmat-admin's picture

I use number lines in the lessons mainly so students have a secondary (visual) way to understand inequalities. That said, drawing a number line during the test doesn't take long, so if doing so helps you organize your thoughts, I'm all for it.

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