David is trying to decide if it makes sense to outsource the purchasing function. He has a chain of $12$ restaurants and employs two buyers at an annual fixed cost of $$85,000.$ David estimates that the variable cost of each purchase order placed is $$15.$ An outsourced company will perform the purchasing function for a fixed annual fee of $$100,000$ plus $$5$ for each purchase order placed. Last year, David placed $1400$ purchase orders. $($show your work$)$

What was the in$-$house purchasing cost last year?

What would the cost be if outsourced?

If David estimates it will place $1800$ purchase orders next year, should David outsource?