Answer
Purchase of $16$ hats, for a price of ${{\$}} 23.16$ per hat.
Work Step by Step
Using the graphing window used in part (a), adjusting to $[0,40] $ by $[20,35],$
we cancel the graphs for the cases other than case $B$.
We estimate that the graph is at its lowest point at $(15.811,23.162)$, so we graph the vertical line $x=16$ and find the intersection,
representing the purchase of $16$ hats, for a price of ${{\$}} 23.16$ per hat.
