Question from MST Exam

[guanjennifer]

The question is

|x-3| < 5

Quantity A
The least possible value of x

Quantity B
-2

I answered C, but the test said the correct answer was A.

Is this a mistake?

[okoronkwoac]

It is not a mistake. They are correct. Look at the solution this way.

|X-3| < 5
this implies that: X-3 < 5 or X-3 > -5
the least possible value of X of course will come when X-3 > -5

if : X-3 > -5
add +3 to both sides to null out the -3:
X -3+3 > -5+3 or X > -2
If X > -2 it follows that the least possible value of X would be greater than -2.

Therefore, Quantity A is always greater than Quantity B.

[tommywallach]

Hey Guys,

Okoronk is absolutely right.

An important lesson for doing QC well is to never think you know if something is going to happen just by looking at it/theorizing. Instead, try out values trying to prove D. Do not pick D until you have definitively found values that create D (i.e. a situation where column A is bigger than column B as well as a situation where the two columns are equal).

Good luck!

-t

[guanjennifer]

I see what I was doing wrong. I read the problem as ≤ the whole time.

Thanks!

[tommywallach]

That'll do it. No worries! Good luck with all your future studies!

-t