Calculates sum of a list of time shares in format min:sec

sum_time_shares.rb

# str = "1:42 + 07:48"
# output = "9:30"
def sum_time_shares(str)
  values = str.gsub(" ", "").split("+")

  total_seconds = values.reduce(0) do |sum, value|
    minutes, seconds = value.split(":")
    sum += (60 * minutes.to_i) + seconds.to_i
  end

  "#{total_seconds / 60}:#{total_seconds % 60}"
end