Darius wants to purchase his favorite salad dressing. The salad dressing comes in two different size bottle. The 16 ounce bottle is on sale for $3.36. The 10 ounce bottle is priced at $2.30. Darius has a coupon for 40 cents off if you buy two 10 ounce bottles. Determine if Darius gets the better buy when he buys one 16 ounce bottle or when he buys two 10 ounce bottles.

The answer is: there is no difference. The price for one 16-ounce bottle is $3.36. Therefore, the price for 1 ounce will be: 16 ounces : $3.36 = 1 ounce : x. x = $3.36 * 1 ounce : 16 ounces. x = $0.21. So, in this case 1 ounce is $0.21. The price for two 10-ounce bottles with the coupon for 40 cents off is: 2 * $2.30 - $0.40 = $4.60 - $0.40 = $4.20. Therefore, the price for 1 ounce will be: 20 ounces : $4.20 = 1 ounce : x. x = $4.20 * 1 ounce : 20 ounces. x = $0.21. So, in this case 1 ounce is $0.21. Thus, there is no difference if he buys one 16-ounce bottle or when he buys two 10-ounce bottles.