The boundary of a lake is $$600\text{m}$$ long. Trees are planted at regular intervals of $$6\text{m}$$ round the lake. How many trees are planted round the lake? 
Overseas Competition->Knowledge Point->Word Problem Modules->Interval Problems->Circular Paths
In the case of circular tracks,  number of intervals $$=$$ number of trees,  $$600\div 6=100$$,  $$100$$ trees are planted round the lake. 