**cost

Could someone break this down Barney style for me?

The manager of a frozen Air Referigerator factory notices that on Monday it costs the company a total of $25,000 to build 30 referigerators and on Tuesday ot cost $30,000 to build 40 referigerators.

(a) Find a linear cost function based on this information

**when I think linear cost function i want to put it in this form** **c(x) = marginal cost(x) + Fixed cost** **soo.. do I multiply 25000*30=750,000** **then... 30,000*40=1,200,000** **then i get stuck!**
(b) What is the daily fixed cost?