Since Cory drives his wheelchair at 12 miles per hour, then Milo rolls downhill on his skateboard at 12/2 = <<12/2=6>>6 miles per hour.
Therefore, Milo runs at 6/2 = <<6/2=3>>3 miles per hour.
If Milo runs for 2 hours at 3 miles per hour, then Milo will travel 2 * 3 = <<2*3=6>>6 miles.
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