This is inspired by a troll on another thread, but how long could you run each race at WR pace? Also, assuming that you in your peak fitness.
Marathon: 2.5 miles
Half Marathon: 1.8 miles
10k: 1.15 mile
5k: ~ 1400m
1500: 600-700m
800: 400m
400: can't even get up to that fast
200: can't even get up to that fast
100: can't even get up to that fast