Answer: The correct answer is $16.1 per unit.
Step-by-step explanation:
C(x) = 9000 + 6x + 0.05x²
C(100) = 9000 + 6 × 100 + 0.05(100)²
= 9000 + 600 + 500
= 10,100
C(102) = 9000 + 6 × 102 + 0.05(102)²
= 9000 + 612 + 520.5
= 10,132.2
Now, the average rate of change of C with respect to x when production level changed from x = 100 to x = 102 is :
⇒

=

= $16.1 per unit