An invoice is a document given from the seller to the buyer stating the quantity of products bought, agreed prices and transactions made between the two parties. If the buyer bought the product in June 10 and decides to pay on the 19th, only 9 days have passed since the date of purchase. This is inclusive of the agreement written that 2% discount is given if paid not more than 10 days. Therefore, the check should be
($5,000)(1-.0.02) = $4900