Final answer:
The common unit rate for solving speed problems is kilometers per hour or miles per hour.
Step-by-step explanation:
The common unit rate you would use to solve a problem involving the speed of a vehicle is kilometers per hour or miles per hour.
For example, if a car travels 60 kilometers in 1 hour, the unit rate would be 60 kilometers per hour.
Similarly, if a car travels 40 miles in 2 hours, the unit rate would be 20 miles per hour.
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