Answer:
The average speed of Omar for the entire trip from home to the gift store and back is 15 mph.
Explanation:
It is given that Omar traveled uphill to the gift store for 30 minutes at just 10 mph.
1 hour = 60 minutes
0.5 hours = 30 minutes
Total distance between home to gift store is

The distance between home to gift store is 5 miles.
Time taken by Omar along the same path downhill at a speed of 30 mph is

Total distance of the entire trip from home to the gift store and back is

Formula for average speed is




Therefore the average speed of Omar for the entire trip from home to the gift store and back is 15 mph.