Answer:
3/4 of an hour.
Explanation:
So Alex walks 3 miles per hour. Since you need to find how much time he will need to get to school, you just have to divide the distance from school by his miles per hour. 2.25/3 which equals 0.75. 0.75 is the percent of an hour he needs to walk 2.25 miles. To find the total minutes, multiply 0.75 by 60 to get 45. It will take Alex 45 minutes to walk to school, which is 3/4 of an hour.
Hope this helped!