Give the step-by-step reasoning process and then the final answer. Grandpa Lou enjoys watching movies on the Hallmark channel, where every movie lasts 90 minutes. If, on Tuesday, he watched several full-length movies on the Hallmark channel for a total of 4 hours and 30 minutes, and then on Wednesday he watched on the same channel twice as many movies as he did on Tuesday. What is the maximum number of full-length movies Grandpa could have watched during these two days?
4 hours and 30 minutes is the same as 4 * 60 + 30 = 270 minutes. At 90 minutes per movie, Grandpa could watch a total of 270 / 90 = 3 entire movies in 4 hours and 30 minutes. On Wednesday, he watched 2 * 3 = 6 movies. Thus, during these two days, he could have watched as many as 3 + 6 = 9 movies.
The final answer: 9.