Zack needs to purchase malt for his micro$-$brew production. His supplier charges $$35$ per delivery $($no matter how much is delivered$)$ and $$1\mathrm{.}20$ per gallon. Zacks annual holding cost per unit is $35\%$ of the dollar value of the unit. Zack uses $20,000$ gallons of malt per week. Assume one year $=50$ weeks.