One of the basic concepts in finance is the................. , which means that a unit of currency received today is worth more than the same unit of currency received at some future. This is why you need to pay interest to the lender when you borrow money. Accordingly, since.................. is essentially money lent to a firm's customers, the amount a firm collects from the customers should be seen as the sum of the value of the product/service sold and the.................. for deferring payment. Following this logic, if a firm can borrow at 3.6% from its bank, the firm would be better off if it can receive payment one month early in exchange for giving a discount less than...................... % (one decimal place).