More free pints doesnt have to be correct!

1 kilometer is 1000 meters.

so 10 laps = 4 kilometers. 

The answer is 30

First, count the distance in 3 days
distance = 3 × distance each day
distance = 3 × 4 km
distance = 12 km

Second, convert the distance to meter
1 km is equal to 1,000 m
distance = 12 km
distance = 12 × 1,000 m
distance = 12,000 m

Third, determine the number of laps
laps = distance/each lap
laps = 12,000/400
laps = 30

Kali run 30 laps in 3 days