On June 1, 2020, merchandise subject to terms 1/10, n/30, FOB shipping point, is sold on account to a customer for $18,000. Transportation cost amounted to $1,000 were paid directly to the shipping company. On June 3, the seller issued a credit memorandum for $4,000 for returned merchandise. This was prior to payment by the customer.

1. What is the amount of cash collected by the seller if the payment is made by the customer on June 8, 2020?

2. What is the amount of cash collected by the seller if payment is made by the customer on June 21, 2020?