Last month, the average price for half gallon of milk in Kroger was $2.05. Now this month, the average price for half gallon of milk in Kroger was $2.25. Which of the following could be used to calculate the percent of increase, p, in the price for half gallon of milk?
A 0.20/ 2.25 = p100
B 0.20/2.05 = p100