Question 388806
Per cent means "per one hundred".
In place of "what per cent" I can
put in {{{x/100}}}
Now I just read the sentence
$168 is {{{x/100}}} x $560
or
{{{168 = (x/100)*560}}}
Multiply both sides by {{{100}}}
{{{16800 = 560x}}}
{{{x = 30}}}
a commission of $168 on $560 
is a commission Of 30 per cent