solution.rb

class Vehicle
  attr_reader :color, :wheels, :status

  def initialize(args)
    @color = args[:color]
    @status = :off
  end

  def brake
    @status = :stopped
  end

  def drive
    @status = :driving
  end

  def park
    @status = :off
  end

  def needs_gas?
    return [true,true,false].sample
  end
end


class Car < Vehicle

  @@WHEELS = 4

  def initialize(args)
    super
    @wheels = @@WHEELS
  end
end


class Bus < Vehicle
  attr_reader :passengers

  def initialize(args)
    super
    @wheels = args[:wheels]
    @num_seats = args[:num_seats]
    @fare = args[:fare]
    @passengers=[]
  end
 
  def drive
    return self.brake if stop_requested?
    super
  end

  def admit_passenger(passenger,money)
    @passengers << passenger if money > @fare
  end
 
  def stop_requested?
    return [true,false].sample
  end
end


class Motorbike < Vehicle

  @@WHEELS = 2

  def initialize(args)
    super
    @wheels = @@WHEELS
  end

  def drive
    super
    @speed = :fast
  end
 
  def weave_through_traffic
    @status = :driving_like_a_crazy_person
  end
end


### BUS
puts "BUS"
my_bus = Bus.new({:color => "yellow", :wheels => 4, :num_seats => 30, :fare => 2})
my_bus.admit_passenger("Jake", 1)
my_bus.admit_passenger("John", 3)
p my_bus.drive == :driving
p my_bus.brake == :stopped
p my_bus.park == :off
p "Passengers on bus: #{my_bus.passengers}"

if (my_bus.needs_gas? == false || my_bus.needs_gas? == true)
  puts "OK"
end

if (my_bus.stop_requested? == false || my_bus.stop_requested? == true)
  puts "OK"
end

### CAR
puts
puts
puts "CAR"
my_car = Car.new({:color => "red"})
p my_car.color
p my_car.wheels
p my_car.drive == :driving
p my_car.brake == :stopped

if (my_car.needs_gas? == false || my_car.needs_gas? == true)
  puts "OK"
end

### MOTORBIKE
puts
puts
puts "MOTORBIKE"
my_motorbike = Motorbike.new({:color => "black"})
p my_motorbike.color == "black"
p my_motorbike.drive == :fast
p my_motorbike.brake == :stopped
p my_motorbike.weave_through_traffic == :driving_like_a_crazy_person

if (my_motorbike.needs_gas? == true || my_motorbike.needs_gas? == false)
  puts "OK"
end

vehicle.rb

class Car
 @@WHEELS = 4
 def initialize(args)
   @color = args[:color]
   @wheels = @@WHEELS
 end
 def drive
   @status = :driving
 end
 def brake
   @status = :stopped    
 end
 def needs_gas?
   return [true,true,false].sample
 end
 
end
class Bus
 attr_reader :passengers
 def initialize(args)
   @color = args[:color]
   @wheels = args[:wheels]
   @num_seats = args[:num_seats]
   @fare = args[:fare]
   @passengers=[]
 end
 def drive
   return self.brake if stop_requested?
   @status = :driving
 end
 def admit_passenger(passenger,money)
   @passengers << passenger if money > @fare
 end
 def brake
   @status = :stopped
 end 
 def stop_requested?
   return [true,false].sample
 end
 def needs_gas?
   return [true,true,true,false].sample
 end

 
end


class Motorbike
 @@WHEELS = 2
 def initialize(args)
   @color = args[:color]
   @wheels = @@WHEELS

 end

 def drive
   @status = :driving
   @speed = :fast
 end

 def brake
   @status = :stopped 
 end
 def needs_gas?
   return [true,false,false,false].sample
 end 
 def weave_through_traffic
   @status = :driving_like_a_crazy_person
 end
end