To run a 10k in 40 min, hold 6'26" per mile, i.e. 9.32 mph (4'00"/km). At that pace: 5K in 20'00", 10K in 40'00", half marathon in 1h24'23", marathon in 2h48'47".
10K in 40 min: 6'26"/mile
1 track lap = 1'36"0
1 track lap = 1'36"0
To run a 10k in 40 min, hold 6'26" per mile, i.e. 9.32 mph (4'00"/km). At that pace: 5K in 20'00", 10K in 40'00", half marathon in 1h24'23", marathon in 2h48'47".