Hi there! So there were $2,000 in sales on Monday, and then it dropped by 10% on Tuesday. As you probably know, percents are parts of 100. Even though the sales dropped by 1%, it is still 90% of Monday's sales, because 100 - 10 is 90. 2,000 * 90% (0.9) is 1,800. $1,800 in sales were made on Tuesday. On Wednesday, sales fell another 20%, which leaves 80% of Tuesday's amount still made. 1,800 * 80% (0.8) is 1,440. $1,440 of sales were made on Wednesday. Now, the amount of Thursday's sales increased by 25% of Monday's sales. We can multiply Monday's sales (2,000) by 25% to find what amount that is. 2,000 * 25% (0.25) is 500. Now, we add that to Wednesday's amount to find Thursday's amount. 1,440 + 500 is 1,940. We can find the net change by finding the difference. Net change can be positive or negative. In this case, 2,000 - 1,940 is 60. Sales dropped overall from Monday to Thursday, so the net change will be negative. There. The net change in total sales is -$60.
