Answer:
Average speed =
miles per hour
Explanation:
Formula to calculate the average speed of an object is,
Average speed =

If I travel with the speed of x mph for t hours,
Total distance covered = Speed × Time
=
=
miles
Similarly, if I travel with the speed y mph for t hours,
Total distance covered =
miles
Total distance covered by me =
miles
Total time taken to cover this distance =

=
hours
Therefore, expression for the average speed will be,
Average speed =

=

=
miles per hour