Predicting When the Leading Musher Will Finish – 5th grade style

My school started spring break as of the end of the school day today.  My students were so eager to watch the winning musher together as a class, so I took the opportunity to do some math with them to show ABOUT when the leading musher will cross the finish line. 

Please know that I did tell them that the leader at the time isn’t necessarily going to win but our math problem was a lot of IFs……

If the leading musher is traveling at an average speed of 7 mph and has 190 miles to go, how long will it take him to cross the finish line in Nome?

  1.  We rounded the average speed of 6.7 to 7.
  2. I reminded them that we can work in powers of 10 and don’t have to look at 190 miles (the remainder from the official 998 miles to his current spot at mile 808) but can look at 19.
  3. They rounded 19 to 21 for estimation purposes so then we had 21/7 = EASY!
  4. 30 hours once we multiplied by 10…but WAIT….that is if he NEVER stops running!
  5. Factor in the run/rest schedule (drawn like it shows on the GPS tracker) of 6 hours each and the total hours was bumped to 54.
  6. BUT WAIT! There is a mandatory 8 hour layover in White Mountain. Now he was up to 62 hours.
  7. We figured 24 hours at a time from 10 a.m. our time today and got a ROUGH estimate that he would finish exactly at midnight Wednesday.

And, of course, I reminded them that ANYTHING can still happen and…

NONE of us want to be in school at midnight on Wednesday, so no, we won’t watch the finish together. But I sure did appreciate their enthusiasm and their math logic and calculation skills.