How did they get these answers? The bolded ones are the answers.

Consider a rm that uses capital K and labor L to produce output 3;. The rm's production function is f[K, L) : 3K%L%. The price of labor and capital are both 1, and the price of output is 9. 5. (8 points) What is the rnl'e demand for capital and labor? A. K = 125, L 2125 B. K = 1000, L = 1000 C. K = 012, L 2 I312 D. K : 8, L = 8 . (8 points} What is the rm'e total output? A. 4 I3. 100 C. {34 D. 300