12,000miles;5%increase
find 5% of 12000 then add that to 12000percent means parts out of 100 so 5%=5/100=0.5/10=0.05/1=0.055% of 12000'of' means multiply so 0.05 times 12000=600add this to 1200012000+600=12600the answer is 12600 miles