Write the unit rate for the situation. 210mi in 3hr

To determine the unit rate, all you would have to do is simply, take the measurement of distance and divide by the unit of time, so it would be 210 miles/3 hours = 70 miles/hr.

Unit simply means one. So find the rate the object is moving in 1 (unit of time) in this case hour.

I think you could say the unit rate would be 210 miles/3 hours = 70 miles/hr.