What does it mean to be 70 miles closer to the finish than to the start? Let's suppose he is half way. He would be 150 miles from the start and 150 miles from the finish. So, he is no closer to the finish than he is to the start. So, at that point it would be zero. Now, let's say he traveled one more mile. Now he would be 149 mi from the finish and 151 miles from the start. So, we could say he is 2 miles closer to the finish than the start. Thinking about this, it must be then when he is 35 miles past the mid point he must be 70 miles closer to the finish than the start. That is, 185 from the start minus 115 miles to the finish = 70 miles. I guess the solution is 185.
Notice that the amount of time is not used in this solution.
