[Tai_Chung]

Aren’t boarders discriminatory?

[Daffynition]

The answer is Dog. *Maths. I'm onaroll*

[CatherineofAragon]

Math is above my pay grade.

[ViLaLuz]

10 units form the borders on all four sides.

[editor-surveyor]

.
None of the above!

Four times the square root of 12 would give the minimum number for the length of the border, which is 13.856, so 14 is the closest answer of those offered.

.

[GOYAKLA]

Try this one! Very simple.
Take a wooden 3” Cube paint it. Then cut it into 1” cubes.
How many cubes have just/only one side painted?_____
How many cubes have just/only two sides painted?______
How many cubes have just/only three sides painted?______

Your problem’s answer is 14 units, link
http://wyattsallstars.wikispaces.com/file/view/Lesson+13-8+practice.pdf
They are working on perimeters?

[cynwoody]

Blankets are generally rectangular, with a reasonable aspect ratio. If we assume 4x3 (aspect ratio 1.33333), the area is 12, and the border length is B: 14. Duh!

Of course, the customer might have ordered a long blanket, say 9.19493 units long by 1.30507 wide. In that case, the correct answer is D: 21.

Or maybe the customer had in mind an aspect ratio closer to 2.26. In that case, a 5.18614 by 2.31386 blanket would fill the bill and require a border of 15 units, answer C.

Or maybe the customer wants something special, say a circular blanket. In that case, the blanket needs to be 3.90882 wide, with a border measuring 12.27992 units. That answer doesn't appear.

The problem is improperly specified. Teach fails!

[NTHockey]

I used to have a college Physics professor who gave multiple choice tests. Invariably, one question had no right choice. And he would then throw out that question - even when we’d write the correct answer! Drove the class nuts.

[The_Reader_David]

Having flogged the question to death mathematically, we can have even more fun by considering the practical matters that add another layer of ill-posedness:

Perhaps the blanket is rectangular has selvedge along one side (intended to be the bottom) and a border is needed only on three sides, or selvedge along two sides (used as the long sides) and a border is needed on only two.

Perhaps the border material is crocheting cotton, in which case the correct answer depends both on the perimeter of the blanket and the crocheting pattern used (and will be much larger than the perimeter in linear units).