Can you walk me through the solution of: When Pogo, the four-legged martian, walks across the soft Martian soil, it leaves 4 footprints every meter.  But Grimzi, the three-legged Plutonian, leaves only 3 footprints in the soft sands of Pluto for every 6 meters it walks.  If Pogo travels 6000 meters across the soil of Mars, and Grimzi travels for 6000 meters across the fine sands of Pluto, what is the combined total number of footprints the two creatures will leave on the surfaces of their respective planets?