I need to understand measurement and mensuration

continuous data.  I do not understand how to make it work for example

A car travels at a constant speed of 70km per hour for a time of 2 hours and 45 minutes.  Its speed is quoted to the nearest km/h and the time is quoted to the nearest minute.

Calculate:

a) the maximum possible distance that the car could have travelled

b) the minimum distance the car could have travelled

This is just an example I have copied from a text book it is not part of any assignment.