Answer:
20 posts are needed for 100m of fence.
Step-by-step explanation:
This question can be solved by a simple rule of three.
Fence posts are to be placed in a row 5 m apart.
This means that 1 post is needed for 5m of fence.
How many posts are needed for 100 m of fence?
1 post - 5m
x posts - 100m
5x = 100
x = 100/5
x = 20
20 posts are needed for 100m of fence.