Ann works in a supermarket for $10.00 per hour. if her pay is increased to $12.00, then what is her percent increase in pay ?

It's 20% increased, because it increased by $2, $2 goes into $10 5 times, and if you were to put that into percentages 2 is a fifth of 10 so that would 20%, because 20 is a fifth of 100.