graph

eddy2017

eddy2017

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Hi, I need your help in how to go about solving this question.

The 25 students of III C, after collecting the grades achieved in the written test of mathematics, have constructed the following graph. How many students achieved as a grade 7?


Voti di matematica della classe 111C = Grades from 111 C class.
the word Voto i nthe graph means grade.
the rest is a piece of cake for you all. Not for me! :)

1608406998684.png
 
Can i write a proportion?. As in,
25 = 12% (the ones who got 7)
100% 7
 
eddy2017 said:
Can i write a proportion?. As in,
25 = 12% (the ones who got 7)
100% 7
Click to expand...
No!

Your ratio

\(\displaystyle \frac{25}{100}\ \ \frac{no. \ of \ students}{percent} \ \ = \ \ \frac{12}{7}\ \ \frac{grade}{no. \ of \ students}\)


Why should \(\displaystyle \frac{no. \ of \ students}{percent}\) be equal to \(\displaystyle \frac{grade}{no. \ of \ students} \ \ \)??

This is NOT even like claiming apple = orange.
 
I am sorry, but did not understand your reply.
How then should the ratio be set up?.
Don't tell me rightaway, just lead me there, please. I want to learn to reason it out.
 
Thanks, Mr Khan. I found help. It was so easy.
12% of the 25 students in the class received a grade of 7, so I calculate 12% of 25 which is 3.
Thanks again for your reply and sorry if i struggle to see how to do it at first.
 
If the unfriendly percent bother you then temporarily change it to a more friendly value, say 50%. If 50% of the students got a particular grade that half of the students got this grade. You compute 1/2 of 25 (which unfortunately is 12 1/2). 50% = 50/100 = 1/2. So for 12% you compute 12/100* 25 = 3.
 
Noted, Jomo. Thanks a lot. I always knew it had to do with percent but never saw it. Skeeter brought my attention to it.
Once you see what you have to do it becomes a lot easier, you know that. the 12% * 25 was pretty straightforward.
Your proposition goes though.
Thanks.
 
eddy2017 said:
Hi, I need your help in how to go about solving this question.

The 25 students of III C, after collecting the grades achieved in the written test of mathematics, have constructed the following graph. How many students achieved as a grade 7?


Voti di matematica della classe 111C = Grades from 111 C class.
the word Voto i nthe graph means grade.
the rest is a piece of cake for you all. Not for me! :)

View attachment 23872
Click to expand...
If I wanted to set the problem as a ratio problem - then I would first define:

No of students getting 7 = N

then

(25/100) (#student/%) = (N/12) (#student/%)

(25/100) = (N/12)

N = 12 * 25/100 = 3 students
 
Great, Mr Khan. Thank you so much. It helps a lot seeing it as a ratio too.
 
I am so glad that there was a comma between Great Mr Khan. He was changed since his title has become SUPER, I can't imagine if his new title became great.
 
You could also note that "12% of 25" is the same as "25% of 12" and 25% of anything is 1/4 of it.
 
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