$3.($Inventory Management $-$ Part $1)$ An electrical repair firm inventories three kinds of small motors. The pertinent data is shown below. The inventory carrying charge is given as $0\mathrm{.}15.$ Management has decreed that no more than $\backslash (\backslash$$ $8000\backslash )$ can be invested in inventory at any point in time. Additionally, the warehouse has only $7500$ square feet that can be allocated to these motors. Find the optimal inventory policy for these motors.