Sarah is going to the store 2.5 miles away. she has only 15 minutes to get there before they close. at what average speed must she ride to get to the store before they close?

Sarah must has to ride with average speed 10 miles per hour.

Step-by-step explanation:

Average Speed tells the rate at which object is travelling his whole journey.

∴  

⇒  

⇒ Average Speed = 10 miles per hour

Hence, Sarah has to travel with average speed more than 10 miles per hour.