Question

The annual revenue of a small store, in thousands of dollars, is given by R(t)=645+21t, where t is the year, with t=0 corresponding to 2000. Similarly, the store’s annual profit is given by P(t)=175+16t-0.3t^2.
a). Write the formula for the annual cost function C(t) for the store.
b). Compute C(3) and interpret your result in this context.