@packages = ["2", ["4", "2", "1"], "4", ["4","2"], ["5", "6"]]

@packages = ["2", ["4", "2", "1"], "4", ["4","2"], ["3", "2"]]
@opposites = ["2", "4"]

@packages.reject! { |p| p.is_a?(Array) && (@opposites & p).size >= 2 }

@packages.reject { |a| a.is_a?(Array) && (a & [ '2', '4' ]).length == 2 }

>> @packages = ["2", ["4", "2", "1"], "4", ["4","2"], ["5", "6"], ["1", "2"], ["4", "11"], ["2", "2", "4"]]
=> ["2", ["4", "2", "1"], "4", ["4", "2"], ["5", "6"], ["1", "2"], ["4", "11"], ["2", "2", "4"]]
>> @packages.reject { |a| a.is_a?(Array) && (a & [ '2', '4' ]).length == 2 }
=> ["2", "4", ["5", "6"], ["1", "2"], ["4", "11"]]

rejects = %w(2 4)
@packages.reject { |a| a.is_a?(Array) && (a & rejects).length == rejects.length }

@packages.reject{|element| element.is_a?(Array)}