Question

30 percent of what number is 12

Answer 1

Another way of saying this is "12 is 30% of what number." Knowing that "of" is code word for "multiply" and 30%= 0.30, we can set up this equation, where x = the unknown number:
$12=0.30x$

To solve for x, all we have to do is divide both sides by 0.30, like so!
$12=0.30x \\ \frac{12}{0.30} = \frac{0.30}{0.30}x \\ x=40$

The answer is x = 40, or 30 percent of 40 is 12.

Hope this helps!

Answer 2

 30       12
-----  =  -----
100       x

30x = 1200
    x =  40