Answer:
answer is $5.12
Explanation:
Using the formula two and replacing the given values: 
 
Sale Price = Original Price - Amount Saved. So, 
 
Sale Price = 6.40 - 1.28 
 
Sale Price = $5.12 (answer) 
 
This means, the cost of the item to you is $5.12. 
 
You will pay $5.12 for an item with original price of $6.40 when discounted 20%. In other words, if you buy an item at $6.40 with 20% discounts, you pay $6.40 - 1.28 = $5.12 
 
Suppose Have you received a amazon promo code of 1.28. If the price is $6.40 what was the amount saved in percent: 
 
3) 1.28 is what percent off $6.40? 
Using the formula two and replacing the given values: 
 
Amount Saved = Original Price x Discount % /100. So, 
 
1.28 = 6.40 x Discount % / 100 
 
1.28 / 6.40 = Discount % /100 
 
100 x 1.28 / 6.40 = Discount % 
 
128 / 6.40 = Discount %, or 
 
Discount % = 20 (answer)