A baseball team plays in a stadium that holds 64000 spectators. With the ticket price at $8 the average attendance has been 25000. When the price dropped to $4, the average attendance rose to 32000. Find a demand function $\displaystyle {D}{\left({q}\right)}$, where $\displaystyle {q}$ is the quantity/number of the spectators. (Assume $\displaystyle {D}{\left({q}\right)}$ is linear)

$\displaystyle {D}{\left({q}\right)}=$ Preview Question 6   (For best results, keep answers in fraction form, not decimals)