# Thread: Very easy percentage question, cant remember how to solve it! :(

1. ## Very easy percentage question, cant remember how to solve it! :(

Ok so I took an exam, and they said I got a 53% on it, but when I add up all the percentages and divide by the number of categories, I get a 57% (55% is passing). So can someone tell me what the total percentage (score) of all these categories are? I know this is elementry but I just want to double check before I call them

These are each of the sections of the exam and what I scored:
1) 75%
2) 53%
3) 50%
4) 50%
5) 20%
6) 100%
7) 50%
8) 75%
9) 0%
10) 100%

Thank you so much for the help!

2. Originally Posted by coachscore
Ok so I took an exam, and they said I got a 53% on it, but when I add up all the percentages and divide by the number of categories, I get a 57% (55% is passing). So can someone tell me what the total percentage (score) of all these categories are? I know this is elementry but I just want to double check before I call them

These are each of the sections of the exam and what I scored:
1) 75%
2) 53%
3) 50%
4) 50%
5) 20%
6) 100%
7) 50%
8) 75%
9) 0%
10) 100%

Thank you so much for the help!
If each section carries equal weight then take the mean:

$\displaystyle \mu = \frac{75+53+50+50+20+100+50+75+0+100}{10}$

If each section does not carry equal weight then it's more complicated:

$\displaystyle \frac{0.75x_1 + 0.53x_2 + 0.5x_3+0.5x_4+0.2x_5+1x_6+0.5x_7+0.75x_8+0x_9+1x_{ 10}}{x_1+x_2+x_3+x_4+x_5+x_6+x_7+x_8+x_9+x_{10}}$

Where $\displaystyle x_1 \text{ , } x_2 \text{ , ... , }x_{10}$ are the percentage of the total expressed in decimal/fractional from for questions 1 to 10 respectively

3. Ok, your first problem was my exact thinking, which brought me to 57.x.

4. I get the same answer when I evaluated the first equation. Perhaps a mistake was made?

5. I can only hope! I will call them now.