Abus travels 36 miles in 45 minutes enter the number of miles the bus travels in 60 minutes at this rate

First off, you can start with the 36 and 45.  If 45 is 3/4 of 1 hour, divide it and 36 by 3.  Now we have 15 minutes, (1/4 hour) and 12 miles.  Lastly, to find mph, we can do *4 and we get 4/4 hours, (1 hour) and 48 miles.

What am i doing here. add?