Help with percentages?

My chemistry teacher gave us this really hard math review on the first day and we don't have textbooks yet or anything... I totally forgot how to do these.
Can you guys please walk me through these types of problems?:

"How many percent of 111 is 28?"

"58% of what number is 30?"

"Find 70.1% of the number 139."

Thanks!

Anonymous2012-09-05T02:50:05Z

Favorite Answer

"How many percent of 111 is 28?"
(28/111)*100 = 25.23%

"58% of what number is 30?"
Let this number be "x."
0.58x = 30
x=51.7241379

"Find 70.1% of the number 139."
(70.1/100)*139 = 97.439