The cost of packing a box of chocolates is given by x2, where x is the number of chocolates (a box can never have fewer than 3 chocolates). if the weight of a box of chocolates is given by x + 2, what is the cost of packaging per weight unit?

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

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.

Because this is an equiangular triangle, we can set any two sides equal to each-other to solve for x, because all sides are the same length.

5x - 22 = 4x - 10

Subtract 4x from both sides.

x - 22 = -10

Add 22 to both sides.

x = 12

The value of x is equal to 12.