input: Write a python function to round each element in a given list of numbers, compute the total sum, and then multiply it by the length of the list.
  assert round_and_sum([22.4, 4.0, -16.22, -9.10, 11.00, -12.22, 14.20, -5.20, 17.50])==243
  assert round_and_sum([5,2,9,24.3,29])==345
  assert round_and_sum([25.0,56.7,89.2])==513
output: def round_and_sum(lst):
      rounded_sum = sum(round(num) for num in lst)
      return rounded_sum * len(lst)