An environmental group estimates that the cost of removing x percent of heavy metals from a contaminated site is
C(x) = 56000x / 100 - x dollars
a. What is the cost of removing 90% of the heavy metals?
b. Evaluate limx→100- C (x).
c. Write a sentence to interpret your result in part (b). Also explain why limx→100+ C (x) can not be considered.