Just add their kinetic energies! But don't forget to convert the units:
10⋅102 m/h is 10⋅102/3600=0.28 m/s.
Now 20⋅109 mm/yr. 1 meter has 1000 millimeters, 1 year is 365 days long each 24 hours long each 3600 seconds long:
[365⋅24⋅3600]⋅100020⋅109=0.634 m/s.
The kinetic energy of a body is
KE=mv2/2. The kinetic energy of our system is
KE=21(0.09⋅0.282+0.014⋅0.6342)==6.34⋅10−3 J.
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