759: 3x9
Divad27182 (Talk | contribs) (fix date according to http://www.xkcd.com/archive/) |
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{{comic | {{comic | ||
| number = 759 | | number = 759 | ||
| − | | date = June | + | | date = June 28, 2010 |
| title = 3x9 | | title = 3x9 | ||
| image = 3x9.png | | image = 3x9.png | ||
Revision as of 18:53, 23 February 2013
| 3x9 |
 Title text: Handy exam trick: when you know the answer but not the correct derivation, derive blindly forward from the givens and backward from the answer, and join the chains once the equations start looking similar. Sometimes the graders don't notice the seam. |
Explanation
In college courses with a very large number of students (picture the huge, tiered, amphitheater-style lecture halls shown in any movie or tv show about college), teaching assistants are employed to help the professors grade student work. In math and science cources, students are expected to solve the problems and show their work as supporting evidence. Due to the high volume of work to grade, whether it's being done by the professor or a TA, the grader will get lazy and look for correct answers and the existence of work without checking that the work is accurate.
Transcript
[A problem is given on an arithmetic test: "4) 3x9=?". In handwriting, the student's work follows. The student has accurately reformatted the question as 3 times the square root of 81, which visually resembles the long division problem of 3 divided into 81, and then solved the latter to get 27--the correct answer to both.]
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