What do horse racing, competitive swimming, stock car racing, speed skating, many track and field events, and some scientific experiments have in common? The need for some sort of stopwatch, and people to interpret the data. For competitive athletes in speed-related sports, finishing times (and split times taken at various intervals of a race) are important to help the athletes gauge progress and identify weaknesses so they can adjust their training and improve their performance. • Three girls ran the following times for one mile in their gym class: Julie ran 9:3 3 .2 (9 minutes,

33.2 seconds), Maggie ran 9:44.24 (9 minutes, 44.24 seconds), and Mel ran 9:33.27 (9 minutes,

33.27 seconds). In what order did they finish?

Solution:

The girl who came in first is the one with the fastest (smallest) time. Compare each time digit by digit, starting with the largest place-value. Here, that would be the minutes place:

There is a “9” in the minutes’ place of each time, so next, compare the seconds’ place. Since Maggie’s time has larger numbers in the seconds’ place (44 ) than Julie or Mel (33 ), her time is larger (slower) than the other two. We know Maggie finished third out of the three girls. Now, comparing Julie’s time (9:3 3 .2 ) to Mel’s (9:3 3 .27 ), it is helpful to rewrite Julie’s time (9:33.2 ) so that it has the same number of places as Mel’s. Julie’s time needs one more digit, so adding a zero onto the end of her time, it becomes 9:33.20 . Notice that Mel’s time is larger (slower) than Julie’s (27 > 20 ). This means that Julie’s time was fastest (smallest), so she finished first, followed by Mel, and Maggie’s time was the slowest (largest).

1. Put each set of times in order from fastest to slowest. a. 5.5 5.05 5 5.2 5 .15

Fastest

Slowest

b. 6:06.04 6:06 6:06.4 6:06.004

Fastest

Slowest

2. The table below gives the winners and their times from eight USA track and field championship races in the men’s 100 meter run. Rewrite the table so that the times are in order from fastest to slowest. Include the times and the years. Please note that the “w” that occurs next to some times indicates that the time was wind aided.

Year

2005 Justin

2004 Maurice

2003 Bernard

2002 Maurice

2001 Tim

2000 Maurice

1999 Dennis

1998 Tim

Time

10.08 Justin

9.91 Maurice

10.11 Bernard

9.88w Maurice

9.95w Tim

10.01 Maurice

9.97w Dennis

9.88w Tim

Name

Justin

Maurice

Bernard

Maurice

Tim

Maurice

Dennis

Tim

Time

Year

3. The following times were recorded during an experiment with battery-powered cars. Put them in order from fastest to slowest.

a. 1:22.4 1:24.00 7 1:25 1:22.04 1:23 .1 17 1:23 .2 1:24 1:33

Fastest

Slowest

b. 1:18 .3 1:20.22 1:21.003 1:20 1:17.99 1:21.2 1:18 .22

Fastest

Slowest

c. 1:25 1:24.99 1:24.099 1:25.001 1:24.9901 1:24.9899

Fastest

Slowest

4. Write a set of five times (in order from fastest to slowest) that are all between 26:15.2 and 26:15.24 . Do not include the given numbers in your set.