Rando Manufacturing received an invoice dated Dec 10th. The invoice amount is $20,000 less 15% and 18%, with terms 3/20, n/30. a) What date is the cash discount valid until? (0.25 mark) b) What date is the credit period valid until? (0.25 mark) c) How much will Rando have to pay if it does not take advantage of the cash discount? (0.75 mark) . d) How much will Rando have to pay if it pays within the cash discount period? (0.75 mark)