In a bag of money to take to the bank I have only $$5\text{p}$$, $$10\text{p}$$ and $$20\text{p}$$ coins. I have twice as many $$20\text{p}$$ coins as $$10\text{p}$$ coins and half as many $$5\text{p}$$ coins as $$10\text{p}$$ coins. If the bag contains £$$15.75$$, haw many $$20\text{p}$$ coins are there? 
Overseas Competition->Knowledge Point->Word Problem Modules->Equation Word Problems->Word Problems for Linear Equations with One Variable->Solving Other Problems Using Equations