$$Andy$$ had $$84$$ fewer cookies than $$Ben$$ at first. After $$Andy$$ bought~$\tfrac{1}{3}$~more cookies and $$Ben$$ bought~$\tfrac{1}{5}$~more cookies. $$Aandy$$ had~$\tfrac{1}{3}$~as many cookies as $$Ben$$ in the end. How many cookies did $$Andy$$ have in the end? 
Overseas Competition->Knowledge Point->Combinatorics->Patterns of Figures->Change of Quantity