ruby - how can I make this enumeration statement shorter with Array#select or other methods?

Question

I have the following 7 lines of code, how can i made them shorter and less wordy?

max_group_size = 0
wrong_services.each do |service|
  group_size = service.iep_service.group_size
  if group_size > max_group_size then
    max_group_size = group_size
  end
end

Answer 1

max_group_size = wrong_services.max_by{|service| service.iep_service.group_size}.iep_service.group_size

(Editted after comments)

Answer 2

max_group_size = wrong_services.map {|service| service.iep_service.group_size }.max