Veggie Burgers, Incorporated would like to maintain its cash account at a minimum level of $$245,000$ but expects the standard deviation in net daily cash flows to be $$12,000,$ the effective annual rate on marketable securities to be $3\mathrm{.}7$ percent per year, and the trading cost per sale or purchase of marketable securities to be $$27\mathrm{.}50$ per transaction.

What will be its optimal upper cash limit$?$