Tristate Power Corp. sold merchandise to a customer on credit for $$4,000$ with credit terms of $1/10,$ n$/30.$ The invoice was dated June$14.$Which one of the following statements is true? The customer can take a $$40$ discount if the invoice is paid by July $14$ The customer should pay $$3,600$ if the invoice is paid by june $24$ The customer must pay $$4,000$ if paid after June $24$ The customer must pay a $$40$ penalty if payment is made after July $14$