gistfile1.txt

class CashCounterService

  CURRENCIES_BILLS = {
    usd: [1, 2, 5, 10, 20, 50, 100],
    eur: [1, 2, 5, 10, 20, 50, 100, 200]
  }
 
  def calculate_money_received(to_pay, currency=:eur)
    to_pay = to_pay.ceil
    CURRENCIES_BILLS[currency].each do |bill|
      (to_pay / bill).ceil * bill
    end 
  end
end