Lizzy: 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?.
Me: Hmmm, let me think. I think this is the detailed solution:
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. Final answer: 9.