x = number of chocolates >= 3
Cost of packaging, C = x^2
Weight of a box, W = x+2
Cost per weight unit is
C/W = x^2/(x+2)
Note that x >= 3
Create a table as shown below.
x C/W
------- ----------
3 1.80
4 2.67
5 3.57
6 4.50
7 5.44
Answer:
The minimum cost of packaging per unit is 1.80 for 3 chocolates. The cost increases as the number of chocolates in a box increases.