Anyone able to help me out with this problem. I know your supposed to find minimum and maximum values using some kind of derivative equation, but i am not able to figure it out.

E. D. Craft wrote an article developing a pricing model for vanity license plates. In the article
he discusses that increasing the fee for vanity plates by $1 decreases the percentage of a state’s
population that will request them by 0.04%.
a) Recently, the fee for vanity plates in Maryland was $25, and the percentage of the state’s
population that had vanity plates was 2.13%. Use this information to construct the demand
function q(x), for the percentage of Maryland’s population that will request vanity license
plates for a fee of x dollars.
b) Find the fee, x, that will maximize revenue from the vanity plates
c) Repeat a and b by researching a state of your choice.