A certain Canadian company received an invoice dated March 20 from their Cambodian supplier for the ...

A certain Canadian company received an invoice dated March 20 from their Cambodian supplier for the following shipment of goods that they received on April 1.
   2000 jeans at $25.60 each;
   3050 shirts at $15.25 each;
   1000 men hats at $2.50 each;
   1500 women hats at $3.00 each.
The terms of the invoice stated 4/20, n/45 ROG and all items are subject to trade discounts of 15%, 5%.
a) What is the last day of the discount period?
b) What is the amount due if the invoice is paid in full on April 19?
c) If only a partial payment is made on the last day of the discount period, what amount is due to reduce the outstanding balance to $25 000.00?