a) The cost function for the Wichita factory is a piecewise function that takes into account fixed and variable costs associated with production.
b) The piecewise function for the cost per unit for production of units in the Wichita factory is:
C(x) = 80000/ x + 8, for 0 < x ≤ 40000
C(x) = 90000/ x + 6, for x > 40000
c) The cost per unit for 35,000 units is C(35,000) = 80000/35,000 + 8 = 10.29.