HotFoot Shoes would like to maintain its cash account at a minimum level of $$38,000,$ but expects the standard deviation in net daily cash flows to be $$5,300,$ the effective annual rate on marketable securities to be $6\mathrm{.}2$ percent per year, and the trading cost per sale or purchase of marketable securities to be $$170$ per transaction.

What will be its optimal cash return point?