Answer:
The maximum cost is 41 dollars per necklace.
Step-by-step explanation:
The average cost in dollars/necklace is given by :
[tex]C(x)=0.5x^2-7x+65.5[/tex] .....(1)
Where
x is the number of necklaces that are created
To maximize the cost, find the value of x by putting dC/dx = 0
[tex]\dfrac{d}{dx}(0.5x^2-7x+65.5)=0\\\\x-7=0\\\\x=7[/tex]
Now put the value of x = 7 in equation (1).
[tex]C(x)=0.5(7)^2-7(7)+65.5\\\\=41\ \text{dollars per necklace}[/tex]
Hence, the maximum cost is 41 dollars per necklace.