Formulate the equations to model the following all units’ discount problem: that is, if you order 510 units the $25 price applies to all 510 units. Give the cost and order quantity equations (note maximum order quantity is 2000 units):
$30/unit for quantities: 0 \leq Qty \leq 500
$25/unit for quantities: 500 < Qty \leq 1000
$20/unit for quantities 1000 < Qty \leq 2000