1 day = 750 m
1 * 7 = 750 * 7
7 days = 5250 m
Now, since 1 km = 1000 m, this means in order to convert from meters to kilometers you must divide by 1000
5250 / 1000
= 5.25 km
Or, you could do the hard way by going to wolfram alpha / google and typing 5250 m to km.
Hope this helps!