Final answer:
To minimize Glorious Gadgets' total inventory costs, we find the derivative of the cost function, set it equal to zero, and solve for x. The resulting lot size that minimizes costs is rounded down to the nearest whole number. By substituting this value into the cost function, we find the minimum total inventory cost.
Step-by-step explanation:
To find the lot size that will minimize Glorious Gadgets' total inventory costs, we need to determine the minimum point of the cost function, C(x) = 4x + 18000x⁻¹ + 6000. This can be done by finding the derivative of the cost function, setting it equal to zero, and solving for x.
Taking the derivative of C(x) with respect to x:
C'(x) = 4 - 18000x⁻²
Setting C'(x) = 0 and solving for x:
4 - 18000x⁻² = 0
18000x⁻² = 4
x⁻² = 4/18000
x⁻² = 1/4500
1/x² = 1/4500
x² = 4500
x = √4500
x ≈ 67.08
Since the lot size must be a whole number, we round down to the nearest whole number.
Hence, the lot size that will minimize Glorious Gadgets' total inventory costs is 67.
To find the minimum total inventory cost, we substitute the lot size (x = 67) into the cost function:
C(67) = 4(67) + 18000(67⁻¹) + 6000
C(67) = 268 + 18000(1/67) + 6000
C(67) ≈ 417.91
Therefore, Glorious Gadgets should order a lot size of 67 to minimize their total inventory costs, and the minimum total inventory cost is approximately $417.91.