Dennis uses 1 pound of butter for every dozen croissants that he makes.  He needs to make 6 dozen croissants.  The grocery store currently has a promotion for buy one pound of butter get one half off.  If the butter costs $4.00 a pound, how much will it cost him to purchase 6 pounds of butter?
1 pound of butter makes 1 dozen croissants and he needs to make 6 dozen so he needs 1*6 = <<1*6=6>>6 pounds of butter
The butter is $4.00 a pound and currently on sale for buy one get one half off so every unit of 2 pounds of butter will cost 4*1.5 = $<<4*1.5=6.00>>6.00
He needs 6 pounds of butter and the current promotion is for a unit of 2 pounds of butter so he needs to buy 6/2 = <<6/2=3>>3 units worth of butter
The sale price is $6.00 per 2 pounds of butter and he needs to buy 3 units of butter so 6*3 = $<<6*3=18.00>>18.00 worth of butter
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