On Monday, Matt worked for 450 minutes in his office. On Tuesday, he worked half the number of minutes he worked on Monday. On Wednesday, he worked for 300 minutes. How many more minutes did he work on Wednesday than on Tuesday. Think carefully first, then make a decision:
On Tuesday Matt worked 450 minutes / 2 = 225 minutes. On Wednesday Matt worked 300 minutes - 225 minutes = 75 minutes more. So, the answer is 75.