Times for walking

Question:

1. From the gemara in Pesachim (94 a) three times for walking the distance of a mil are derived, 18 minutes, 22.5 minutes, and 24 minutes. A mil corresponds more or less approximately to the modern day kilometer. However, the time units here represent an extremely slow pace of walking. For a regular person, this should take around 5 or 10 minutes at most, even according to the opinion that the amah is longer.
2. Also, in general, the various measurements and mathematical calculations found throughout Chazal are usually rounded off and not exact, yet here, it is an exact amount of time for 2 things which should be very difficult to time exactly, one being how fast an average person takes to walk a mil, and from there to know the time of dawn till sunrise, which in itself cannot possibly be measured exactly.
3. Moreover, these time units are used exactly in various halachas even with regard to Torah prohibitions such as doing melacha after Shabbos or Yom Kippur, or for salting meat, or for chametz when kneading dough for matzos, and so on. So how can we understand the intended meaning of this gemara?

Answer:

Thank you for your question.

1. When looking at things from the way that we walk nowadays, you are correct, we walk faster than that. According to chazal, a person’s regular walking is an amah’s distance between the back of one foot until the back of the other foot, which leaves half an amah (about 11 inches) between feet. (See Mishna Berura 301-3). A mil is 2000 steps. If we calculate 18 minutes times 60 seconds, we get 1080, which comes out that the person is taking about two steps a second. That isn’t so slow, when you calculate such size steps. When we walk, we are spreading or feet apart more than what chazal prescribe, therefore we end up walking quicker. However according to the Shulchan Aruch a step is meant to be with not more than half an amah between feet
2. Please explain what you mean that chazal’s measurements are in general usually rounded off and not exact? Chazal gave exact measurements, 40 seah for a mikva, an eggs worth is the amount of food a person can swallow at one time, the exact amount of cloth a poor person would save and which amount he would throw out, and to numerous other things, and they were not rounded off?
3. While I don’t know the source for the shiur of where chazal got the time of walking a mil, in general, most of the shiurim of chazal were either learned from pesukim or halacha l’Moshe m’Sinai and are an integral part the tradition handed down from Hashem to Moshe at Mt. Sinai. (see Succah 6a). Therefore, it is understandable that these measurement will be determining factors for many Torah prohibitions.

Best wishes