Monday, May 28, 2012

Math Problems for Backpackers

Most of the time, math problems for backpacking involve easy calculations to find the number of miles hiked, hiking pace, or estimates of time to the next landmark.   Backpackers make these estimates all the time, and you get pretty good at estimating your pace for different conditions and terrain.  This is very helpful for planning how far to go, and whether you have enough time before dark to take that extra side trail or linger at a swimming hole.

If I left Woody Gap 8:13 AM, and got to Gooch Gap 3.5 miles away at 9:21 AM, how did I still have time to stop to smell the flowers?

On my solo overnight backpacking trip this weekend, I ended up doing a lot of math that was more complex than usual.  I started at Woody Gap, and did an out and back along the Appalachian Trail to Three Forks.  How would you have solved the following problems:

1.  You end up talking to and then hiking with two friendly thru hikers on their first day on the Appalachian Trail.  They just graduated, and they've been dreaming of this day for years.  They are hiking roughly 1.5 miles per hour, while you hike 2.5 miles per hour on your own.  If it is 2:30 PM now, how long can you hike with them and listen to their engaging and inspiring stories before saying goodbye and striking out at your own pace, if you want to get to certain rocky scenic viewpoint 5.5 miles away for dinnertime (5 PM)?

Who needs a view anyway when dinner looks and tastes this good? (That's baked tofu, fresh broccoli from the CSA, and rehydrated hummus.)

2.  You are at a spring, and the next water source is 6 miles away, over Sassafras Mountain and a bunch of other steep PUDs.   The day is swelteringly hot, you are drenched in sweat, your feet are swollen, and have already done more miles than you have ever backpacked in a single day.  Your pack weighs 13.4 lbs without water, and you will eat your dinner (0.5 lbs) in another hour.  How many liters of water do you get before setting out if one liter of water weighs 2.2 lbs?

Airing out my feet on a cool rock, and "tanking up" at the spring, cause water doesn't weight anything when it's in your belly.


  1. My husband became really good at timing us on our thru-hikes. He had a watch and could gauge it but I started to 'feel' it and could tell when we would arrive. Of course I had off days when the miles seemed to drag on---but my husband new better.

  2. It really is neat how you develop a good sense of your time and pace out there. I love it when I can predict my arrival time. And you are also so right about the off-days too-- they remind me not to take things for granted.