Mr. Willson worked on making his furniture for 3/4 an hour on Monday. On Tuesday, he worked for half an hour. Then he worked for 2/3 an hour on Wednesday and 5/6 of an hour on Thursday. If he worked for 75 minutes on Friday, how many hours in all did he work from Monday to Friday? Let's think first. Chain of thought:
Since there are 60 minutes in an hour, then Mr. Willson worked for 60 minutes x 3 / 4 = 45 minutes on Monday. He worked for 60 minutes / 2 = 30 minutes on Tuesday. He worked for 60 minutes x 2 / 3 = 40 minutes on Wednesday. He worked for 60 minutes x 5 / 6 = 50 minutes on Thursday. So Mr. Willson worked for 45 + 30 + 40 + 50 + 75 = 240 minutes. In hours, it is equal to 240 / 60 = 4 hours.
Therefore, the answer is 4.