conversations.from: human
conversations.value: Tim decides to do a movie marathon.  The first movie is 2 hours long.  The next movie is 50% longer.  And the last movie is 1 hour shorter than the combined time of the previous 2 movies.  How long was his movie marathon?
  Give me a detailed solution.
conversations.from: assistant
conversations.value: The second movie was 2*.5=1` hour longer than the first movie
  So the second movie was 2+1=3 hours long
  That means the first two movies had a combined time of 3+2=5 hours
  So the last movie had a length of 5-1=4 hours
  That means the marathon lasted 5+4=9 hours