Ryan buys a watch on sale for $$20\textbackslash\%$$ off in a shopping mall. He has an additional $$200-$$dollar coupon since he is a member of this shopping mall. The sales tax in his city is $$5\textbackslash\%$$, and he paid $$\textbackslash$2730$$ for this watch. What was the original price of the watch? 
Overseas Competition->Knowledge Point->Word Problem Modules->Word Problems in Economics->Tax Problems
$$\dfrac{2730}{1+5\textbackslash\%}=2600$$,  $$\dfrac{2600+200}{1-20\textbackslash\%}=3500$$. 