The function which represents the cost of producing x hearing aids is given by the following;

(A) The inverse of this function is determined as follows;

(B) From the inverse function we can determine the following;
INPUT = Cost of producing x units
OUTPUT = Number of units produced
(C) To determine the number of hearing aids that could be produced for a cost of 4,000,000;

At the cost of $4,000,000 the number of hearing aids that could be produced is 13,327.