There are several methods of working out problems in percentage terms. Become comfortable with each of them. Simply knowing that percent means "per 100" is not enough.
100 percent = one
This allows "100 percent" to be placed into numerators as needed, and into denominators, and can be placed into both at the same time.
x × 100 percent = x
x ÷ 100 percent = x
next
Percent = .01
This allows 'percent' to be replaced by '.01' anywhere, although it might be more accurate to replace the 'percent' with an accompanying "multiply by .01" or "× .01" substitution.
x percent = x × .01
Over time, handwriting has suffered in legibility and in necessity. Handwriting is much faster now, as pens, pencils, styluses, and fingertips have replaced quills and brushes. As a result, the '.' in '.01' can often be missed, creating an error in calculation. If choosing to practice the "write .01 in place of percent" method, be sure to add a zero digit in front of the decimal point. This is of particular recent importance when doctors and nurses communicate to each other regarding patient medications.
Percent = 0.01
x percent = x × 0.01
Be sure to maintain good order of operations.
1 ÷ x percent = 1 ÷ ( x × 0.01 )
After some time spent growing comfortable with the p-word, begin using the p-sign. Just remember that in computer work, the '%' can mean something a whole lot different than 'percent.'
100% = 1
x × 100% = x
x ÷ 100% = x
1% = 0.01
1 ÷ x% = 1 ÷ ( x × 0.01 )
Percent is a word, but that doesn't mean it is a noun. As an adjective, percent cancels out in ratios, multiplies and divides, and adds as common terms.
5% + 10% = 15%
5 percent cows of 10 percent cows = 0.05 × 0.10 cows
5 percent cows to 10 percent cows = 1/2 cows
Lastly, rewrite percent as "÷ 100."
x percent = x/100
Hopefully this will be of some help.