I will use #15 for an example. First, you figure out how many feet are in 1 mile (which is 5280 ft.) Then, you find how many feet are in 2.5 miles, so you would multiply 2.5×5280 (=13200). Ok, so now you know how many feet are in 2.5 miles, but the problem is asking for inches. You would now take the number of inches in a foot (12") and multiply it by the number of feet you solved before: 12×13200. Your final answer would be 158,400.