At 6'40" per kilometre you run 9.00 km/h, or 5.59 mph (10'44"/mile). 5K in 33'20", 10K in 1h06'40", half marathon in 2h20'39", marathon in 4h41'18".
6'40"/km = 9.00 km/h · 5.59 mph
1 track lap = 2'40"0
1 track lap = 2'40"0
At 6'40" per kilometre you run 9.00 km/h, or 5.59 mph (10'44"/mile). 5K in 33'20", 10K in 1h06'40", half marathon in 2h20'39", marathon in 4h41'18".