Answer:
7.5
Step-by-step explanation:

1.5 hours=90 minutes
Because 90 minutes/ 30 minutes is 3, multiply 3.6 miles by 3 and get 10.8 miles as your final answer
If you find a common denominator for the two, which is 12 it will make it easier to add. So 4 3/12 + 3 4/12 = 7 7/12.
your answer is 7 7/12.