Mary completes a 15-mile race in 2.5 hours. What is her average speed in miles per hour?
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Mary completes a 15-mile race in 2.5 hours. What is her average speed in miles per hour?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
6
Mary completes a 15-mile race in 2.5 hours. What is her average speed in miles per hour?
train