This is somewhat similar to a section of an IQ test (from which American educators are abjured) but which survive as Graduate Record exam: General Section, etc.There is a distinct difference - an IQ test item should be reliably monomodal. To provide reasonable behavior one needs enough terms to extinguish all but one plausible explanation. Here there are insufficient terms for the purpose, accordingly one reads multiple plausible solutions.I expect the question setter had a simple recipe in mind ~ count the triangles, which may comprise those of unit side, two unit sides, and three unit sidelengths. This approach leads to an answer of 13, though even solvers who do count triangles may omit the two unit length sides leading to a solution of 10. Another approach includes prior counts to arrive at a solution. A third approach generates an algebraic expression which satisfies the constraints.So, another bigger triangle with an associated number would invalidate most unwanted choices.
On Wednesday, October 12, 2022 at 01:47:59 AM CDT, John Denker via Phys-l <phys-l@mail.phys-l.org> wrote:
Given:
The first figure has a score of 1.
The second figure has a score of 5.
Questions:
a) What is the score of the third figure?
b) How do you know?
c) How sure are you?
Remarks:
* Hint: It's harder than it looks.
* There's no physics in it per_se, but similar situations
arise in physics All The Time.
* This is not a word game. No wise-guy dirty tricks. The
things that look like triangles are triangles. The things
that look to be congruent are congruent.
* Imagine assigning this to your students. Think about
what you would infer from the various answers you get.
* Hint: This can be used to illustrate an interesting
point, more interesting than the plain numerical answer.
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