Hello! To solve this problem, you can just simply write and solve a proportion. Set it up like this: 22/x = 5/100. This is because we are looking for the cost of the item if the sales tax was $22 and percents are parts of 100. 5 is 5% of 100, so the 5 goes over 100. Cross multiply the values in order to get 2,200 = 5x. Divide each side by 5 to isolate the "x" and you get x = 440. We can check this by multiply by 5%. 440 * 5% (0.05) is 22. There. The cost on the item sold in Lisa's store is $440.
