How would I solve this step by step. There are other questions on Chegg, but none of them explain how they got their answers. I want to know mathematically and and what equations to use to find the answers to the questions below.

Three machines are employed in an isolated area.

They each produce the same 2,000 units of output per month but with different efficiencies: The first requires $20,000 in raw materials, the second $25,000, and the third $28,000 per month.

If the services of the third machine can be hired at a price of $9,000 per month:

Answer the questions below with the same number format as above: for example, if the answer should be thirty thousand dollars, answer as $30,000.

a) The cost to hire the first machine per month should be:

b) The cost to hire the second machine per month should be:

c) If the cost of raw materials halved, but everything else stayed constant (in the market for the final product), what would be the new rental price per month of the first machine?