We have to find how many miles per hour, so just divide:
45/2.75 = 16.36
If we wanted to find how many hours per mile, we would divide:
2.75/45 = 0.061
The answer is 16.36
Hopefully this helps! If you have any more questions or don't understand, feel free to DM me, and I'll get back to you ASAP! :)