...
...
the 30 minute 10k
the 30 min 10k is tougher. I could never break 30 minutes for 10k but ran a 106 1/2 without much problem. I only ran 4-5 1/2s but ran tons of 10k road races in my prime, running typically between 30:15 and 31:30. I ran other 1/2 marathons in 107 and 108.
With the exception of that very suspect time from Wang Junxia in Beijing 1993... no woman has done sub 30:00 for the 10k.
Quite a few have done sub 1:07 for the 1/2, so that should tell you which is best.
sorry, forgot to include that this converter says 30:00 = 1:06:42
One rule-of-thumb for the 5000/10,000 is to double the time and add a minute. Taking this ratio doubles the time (30x2) and adds 2 minutes, plus a little because the rule works for world class times, but that still gets you to 62:30 or better for 20k. 1100meter more should take 3.3 minutes, or 3:20, so you are at 65:50. Same conclusion as the women's time observation. (note that Paula averaged 67:40s for two straight half Ms)
?,Just use the purdy point system on run-down.com thats my fav. but it's not always the case, I myself have trouble with the 10k distance but in a half marathon when I'm feeling good I can get in a great rythem, i find that harder to do in the 10k.