Ned's Sheds purchases building materials from Timber town Lumber for $3,700 with terms of 4/15, n/30. The invoice is dated October 17. Ned's decides to send in a $2,000 partial payment. By what date must the partial payment be sent to take advantage of the cash discount? Considering the scenario from the previous question, if partial payment was sent by the discount date, what is the balance still due on the order?