An estimate for how far a hiker can travel in a half year is the product of the distance traveled per​ day (1, 10, 100) miles per​ day, and the number of days per half year (1800,180,18) This results in an order of magnitude estimate of (18,180,1800,18000) miles per half year​, which is (less or greater than) the distance from New York to California​, which is approximately (300,30000,3000) miles.​ Therefore, a hiker (can, cannot) hike across the United States in a half year. It would take a hiker approximately (0.5 half year, 1.7 half years,0.75 half year,17 half years, 170 half years) to travel from New York to California.