I really want to know. Let’s say, your math teacher gives you a test, and she marks each subject different points.
Ok, and if I done let’s say, half of the test correct, then how can I calculate in the way that gives me the exact percentage?
I mean, 50% of the answer is correct. Or, 80% of the math home work is correct.
How you do this? it’s really interesting.
Sorry for adding a wrong tag, I didn’t know what kind of algebra or something that is part from Math, not physics or Chemistry. You know what I mean?
Answer
If the tests are of different sizes, 1 common way to create an acceptable answer is to calculate the geometric mean.
An example:
A student scores 2/5 on test 1, 3/7 on test 2 and 9/10 on test 3. (40%, 42%, 90%)
A "fair" representation of how well they did could be: $(\frac{2}{5} \times \frac{3}{7} \times \frac{9}{10})^{(1/3)} \approx 0.536\ =53.6\%$
This has the effect of trying to treat each exam equally regardless of total marks of each test.
Opinion - (this is the best way to do it)
Alternatively, you could add up all the scored marks and divide by the total possible marks:
$\dfrac{2+3+9}{5+7+10} \approx 0.636 = 63.6\%$
This has the tendency to bias the results towards whichever test has the most possible marks.
There is no perfect answer sadly.
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