Jack drives at 40 mph for an hour, then at 50 mph for an hour.  What is his average speed?
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Jack drives at 40 mph for an hour, then at 50 mph for an hour.  What is his average speed?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
45\text{ mph}
Jack drives at 40 mph for an hour, then at 50 mph for an hour.  What is his average speed?
train