Comments on: Another Embarrassingly Bad Math Exam Question

By: MrHonner

MrHonner — Mon, 26 Nov 2012 21:54:34 +0000

I’m not sure what you mean. The two lines are on the same plane, but any two lines that intersect are contained in a plane. I’m not sure exactly where you are going with this–can you explain a bit more?

By: Prince

Prince — Mon, 26 Nov 2012 07:54:40 +0000

Isn’t the answer 4? as the two lines mentioned are on the same plane, therefore the fact would be true even if the two planes weren’t perpendicular (which doesn’t hold for all the others).

By: MrHonner

MrHonner — Thu, 18 Oct 2012 01:41:07 +0000

Yes, that is definitely another issue with this problem, although it doesn’t have any bearing on the mathematics.

By: mr bombastic

mr bombastic — Wed, 17 Oct 2012 22:53:56 +0000

Also, to me, DE is drawn in a way that strongly suggests it is the intersection of the two planes.

By: MrHonner

MrHonner — Tue, 16 Oct 2012 19:51:00 +0000

Initially, I wanted to avoid saying “containing planes”, but your point is a fair one. I’ve amended my remark.

Thanks for pointing this out, and moreover, perhaps offering some insight into what misunderstanding created this awful problem in the first place!

By: Andrew

Andrew — Tue, 16 Oct 2012 18:55:28 +0000

It is not true that ‘knowing two lines are perpendicular could never be sufficient information to conclude two planes are perpendicular’. It is true that: knowing two lines, one contained in each plane, are perpendicular could never be sufficient information to conclude two planes are perpendicular. If we know two lines, each one perpendicular to one of the planes, are perpendicular then the two planes are perpendicular. But I agree the question is dreadful, and demonstrates the danger of relying on a diagram to do your thinking for you!

By: MrHonner

MrHonner — Tue, 16 Oct 2012 17:54:36 +0000

Raja-

I imagine the questions are reviewed, but the process was clearly not effective enough in this case (and many others).

Part of the problem is a lack of transparency in the process. With so much focus on “teacher accountablity” these days, more “tester” accountability only makes sense.

And as tests are handled more and more by private enterprises, we’ll see less and less transparency and accountability.

By: Raja

Raja — Tue, 16 Oct 2012 05:26:00 +0000

They should get the papers peer reviewed by teachers from other universities.

By: MrHonner

MrHonner — Tue, 16 Oct 2012 02:40:32 +0000

It’s extremely embarrassing for several reasons. Sadly, even if it were to register with the public, it would be dismissed as merely a “typo”.

By: Sue VanHattum

Sue VanHattum — Mon, 15 Oct 2012 23:55:24 +0000

Wow! That’s a bad one.