Math in the NewsIssue 95

The Iditarod Race

The Iditarod RaceThis year’s Iditarod happens during a particularly harsh winter. This 1000-mile race is an endurance competition for musher and dog alike. In this issue we measure the average speed of the racers.

The Iditarod RaceThe Iditarod Race began in 1973, in part to commemorate a heroic Anchorage-to-Nome delivery of diphtheria serum that made a husky by the name of Balto famous to children the world over. It is now a world-wide sporting event.

The Iditarod RaceThis is the map of this year’s Iditarod Race. This is the Northern route. On odd-numbered years there is a Southern route. As you can see this 975-mile route is not a straight-line distance from Anchorage to Nome.

The Iditarod RaceThis table shows the winning times for the all the racers since the first Iditarod. The first thing to notice is that these times have steadily increased, as mushers have improved their speeds over time. (Table continued on the next slide.)Source: Iditarod.com

Year Days Hours Minutes Seconds

1973 20 0 49 41

1974 20 15 1 7

1975 14 14 43 15

1976 18 22 58 17

1977 16 16 27 13

1978 14 18 52 24

1979 15 10 37 47

1980 14 7 11 51

1981 12 8 45 2

1982 16 4 40 10

1983 12 14 10 44

1984 12 15 7 33

1985 18 0 20 17

1986 11 15 6 0

1987 11 2 5 13

1988 11 11 41 40

1989 11 5 24 34

1990 11 1 53 23

1991 12 16 34 39

The Iditarod RaceYear Days Hours Minutes Seconds1992 10 19 17 151993 10 15 38 151994 10 13 2 391995 9 2 42 191996 9 5 43 01997 9 8 30 451998 9 5 52 261999 9 14 31 72000 9 0 58 62001 9 19 55 502002 8 22 46 22003 9 15 47 362004 9 12 20 222005 9 18 39 312006 9 11 11 362007 9 5 8 412008 9 11 46 482009 9 21 38 462010 9 23 59 92011 9 18 46 392012 9 4 29 26

The Iditarod RaceTake the data in the table and input it into a spreadsheet. Create a new column to convert the times to hours.

Year Days Hours Minutes Seconds Hours

1973 20 0 49 41 480.831974 20 15 1 7 495.021975 14 14 43 15 350.721976 18 22 58 17 454.971977 16 16 27 13 400.451978 14 18 52 24 354.871979 15 10 37 47 370.631980 14 7 11 51 343.20

=B2*24+C2+D2/60+E2/3600

The Iditarod RaceCreate a line graph of the data for the winning times. Here you can see how the winning times have steadily decreased, and now hover around 200 hours.

The Iditarod RaceNow add another column to the spreadsheet to calculate the average speed.

Year Hours Average Speed (mi/h)

1973 480.83 2.0281974 495.02 1.9701975 350.72 2.7801976 454.97 2.1431977 400.45 2.4351978 354.87 2.7471979 370.63 2.6311980 343.20 2.841

=975/F2

The Iditarod RaceHere is a line graph of the speed data, and it clearly shows a steady improvement in the average speed.

The Iditarod Race

Why have the times increased so steadily?

The Iditarod RaceFirst, let’s refine our speed estimate. The average speed we calculated assumes the mushers are riding 24/7, which isn’t true. There’s a mandatory 40-hours of rest minimum. Adjust your spreadsheet to see the impact on the speeds.

Year Hours Average Speed (mi/h)

1973 480.83 2.0281974 495.02 1.9701975 350.72 2.7801976 454.97 2.1431977 400.45 2.4351978 354.87 2.7471979 370.63 2.6311980 343.20 2.841

Reduce by 40

The Iditarod RaceHere is a double line graph of the speed data sets, and it clearly shows an increase in the average speed.

The Iditarod RaceNow assume that of the remaining hours, a musher spends between 15% to 20% of their time resting. (People normally spend 33 1/3% resting.) How does this affect the speed? Here is a multi-line graph showing such an adjustment.

The Iditarod Race• Continue investigating ways in which racers have

increased their average speed. Keep these questions in mind:• Do racers maintain the same speed throughout the entire

race? If not, how does their speed vary?• How does the number of dogs used in the race affect the

average speed?• What techniques do racers use to improve their speed?