gistfile1.txt

class Numeric
  def prime?
    basics = (2..10).to_a
    return false if basics.detect { |n| self % n == 0 }
    factors == [1, self]
  end

  def factors
    @factors ||= (1..self).to_a.select { |n| self % n == 0 }
  end

end

Nice solution! Just out of curiosity, was my attempt just way off or was the approach doable but with some minor error/bug?