Question 1061640
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If at time 3 hours, a car has traveled 145 miles, and at time 7 hours, the car has traveled 357 miles, 
what is the car's average rate {{{highlight(cross(of_change))}}} over the given time interval? Include units in your answer.
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It is not clear from the post, to which time interval does the question relate.



Does it relates to the 3-hour interval? - Then the average rate is {{{145/3}}} miles per hour.


Does it relates to the 7-hour interval? - Then the average rate is {{{357/7}}} miles per hour.


If it relates to the entire trip of 3 + 7 hours, then the average rate is {{{(145+357)/(3+10)}}} miles per hour.


I left it to you to make calculations.


By the way, the words  "car's average rate of change" tell a lot about you.

The matter is that such combination of words is not applicable in this context.

The correct term is "car's average rate". 


Watch your terminology !!