A food delivery person can either have shifts on bikes or scooters. A shift on a bike can deliver 10 orders, takes 5 units of energy, and brings in $50 on tips because it is faster. A shift on a scooter can deliver 7 orders, takes 6 units of energy, and brings in $43 on tips.  The delivery person has available 40 shifts a month and has 230 units of energy and must bring at least 320 orders. He must have at least 5 shifts on a scooter because bikes are harder to get. How many shifts on each type of transportation should the delivery person schedule to maximize tips received?