I buy the same chips every week and my bill is normally $90.00. Why am I now being charged $108 for the exact same items? What percentage has the store increased their prices?

Hi there! To find the percent of change, do change/original = x/100. The amount of change means to find the distance between two numbers and the original is the previous price. 108 - 90 = 18. Plug in the values in order to get 18/90 = x/100. Cross multiply the values in order to get 1,800 = 90x. Now, divide each side by 90 to isolate the variable. When you do, you get x = 20. The store increased their prices by 20%.