Question

Of the Grade 6 students surveyed, 12% bring their lunch to school. Suppose 24 sixth graders do this. How many Grade 6 students are at the school?

Answer 1

Do it with a proportion...

12(%)      24(out of total)
----    =   ------
100         x (the total)

Let's do it with the quick 'fish' method.

Go from 24 (the known number in the fraction with the var) and multiply by 100.

2400 you then divide it by 12, which equals 200.

There are 200 kids in total. 

To check: Put 24 over 200= 24/200
Divide 24 by 200=  0.12
Multiply that by 100, which equals 12.

So the final answer is 200.

Answer 2

Let's set up a proportion

$\frac{24}{x} \frac{12}{100}$

Solve:
24 x 100 = 2400
2400/12 = 200
x = 200

Hope this helped! If you have any more questions or don't understand, please comment or DM me. :)