Answer:
60 miles per hour
Explanation:
Consider the structure of the wording: "miles per hour"
The word "per" means for each. There is you clue.
Each is, one of and one of is unit measurement
So the controlling element in this question is that you need to convert the 3 hours into 1 hour.
Using ratio properties
180
3
=
x
miles
1
hour
We need to 'force' the left hand side into the same form as the right. That is: we need to convert the denominator into 1 and see what happens to the numerator.
⇒
180
÷
3
3
÷
3
=
x
1
⇒
60
1
=
x
1
So the unit rate of speed is
60
miles
per
−−−
hour