Alex was having a cookout Friday night and planned to serve burgers to his guests.  He planned to cook 3 burgers for each guest and had invited 10 friends over.  1 of his friends didn't eat meat and said they would bring their own food.  Another one of his friends didn't eat bread and would not need the buns.  The burger buns came 8 to a pack.  How many packs of buns did Alex need to buy?
He invited 10 friends but he didn't need to cook for 1 of his friends so that left 10-1 = <<10-1=9>>9 friends to cook for.
He was cooking 3 burgers per 9 guests so 3*9 = <<3*9=27>>27 burgers
He needed 27 burger buns but 1 guest wouldn't eat the buns so now he needs 27-3 = <<27-3=24>>24
He will need to buy 24 buns and they come 8 to a pack so he needs 24/8 = <<24/8=3>>3 packs of buns
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