Measure from your origin to your destination using either an old-fashioned atlas or a reliable Internet map site. For example, assume a trip is 721 miles. Use the simple equation: Time equals distance divided by rate, or speed. In mathematical writing, this is expressed as T = D/R. In this case, D is 721.
Determine your speed. For estimation purposes, assume a constant or average rate of speed. For example, driving 721 miles at an average of 55 mph would take 13 hours, 6 minutes.
Factor in your variables. Assuming a constant rate of speed is good for practicing your math skills, but it won't do you much good in the real world. Actual travel has plenty of obstacles, such as traffic, blown tires, bathroom breaks and detours. Before leaving on a long trip, allow an extra 10 minutes or so for every 100 miles of your trip.
