We will use conversion factors
1 hour = 60 minutes
We need to make sure to put them so the units cancel
We also know that 1,61 km = 1 mi
1.81 km 60 min 1 mi
---------- * ----------- * ---------------
min 1 hr 1 . 61 km
67.45341615
Rounding to the nearest hundredth
67.48 miles/ hr