Answer: 25.7 miles per hour
Explanation: 3 1/2 miles is also 3.5 miles and since it took him from 11 -12:30 to get to his friends house that an hour and 30 minutes which is also 90 minutes. To get the miles per hour you have to divide the time by miles which is 90/ 3.5 which is 25.7 miles an hour rounded. You can check the work by multiplying miles per hour which is 25.7 to how many miles it took him which is 3.5 and you’ll get how long it took to walk which is 90 minutes.
I DONT KNOW IF YOUR TEACHER WANTED YOU TO ROUND OR PUT IT IN FRACTION FORM BUT I ROUNDED.
I HOPE THIS HELPS AND IF IM WRONG OR YOU NEED A BETTER EXPLANATION FEEL FREE TO COMMENT AND TELL ME SO