Substituting random pick method with arr.sample
Adding challenge: oldest and youngest person
Showing how to write data of a class
Moving challenge from D3_fizz_buzz_game to Challenges
Adding my_hash which could get data from pair class
Understanding the mechanism of hash diving into the details
Changing public method to private
Adding private method found_pair_with_key following DRY
Adding multiples of three and five under a giving natural number