Answer:
The sort of returns to scale the firm face is a decreasing return to scale.
Step-by-step explanation:
The production function is correctly restated as follows:
.................................. (1)
To determine the type of return to scale, the input usages K and L are scaled by the multiplicative factor ∝, and substituting it into equation (1), we can have the following:





Since the sum of the exponents of the multiplicative factor ∝ is 0.9 which is less than 1, the sort of returns to scale the firm face is a decreasing return to scale.