At an electronic store, an air-conditioner marked $280 was on sale at $259. What was the percentage of discount for the air-conditioner?

%

Use the formula:

Discount = Marked Price – Selling Price

Percent Discount = Discount/Marked Price × 100%

Discount: 280 – 259 = 21

The marked price: 280

The percentage of discount: 21 ÷ 280 = 0.075 = 7.5%