Answer:
The distance that the tortoise has still to cover is equal to 80 meters.
Explanation:
When it says that she has only come 4/5 of the total journey that means that if we were to divide the journey into 5 parts of the same length, the turtle would already be done with 4 parts and has only 1 more part to do before finishing the journey.
Since all the parts are of the same length then the distance of that one part that she still has to cover is equal to...
400 / 5 = 80 m
Therefore the distance that the tortoise has still to cover is equal to 80 meters