carbazzy,
The way would be ...

the speed is 1mm/sec....
First convert sec in to day..
There are 24 hrs, and each hr has 60 minutes, which in turn have 60 secs each..
so number of secs in a day = 24*60*60=86400 secs..

So 1mm/sec = 1*86400mm per 86400secs = 86400mm per day ..
Now 1000mm = 1 m, so \(86400mm = \frac{86400}{1000}m=86.4m\)
Thus 86400mm/day=86.4m/day

Similarly you can find km per week...
Now there are 7 days in a week, so 86.4m/day = 86.4*7/7day=604.8m/week..
Convert m into km = (604.8/1000)/week=0.6048km/week
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