$15-9\times1=6$  $6\div(3-1)=3$ pieces of paper were cut. 
There were $$9$$ pieces of paper. Some of them were cut into three pieces. As a result, there are now $$15$$ pieces of paper now. How many pieces of paper were cut? ($$2005$$ Math Kangaroo Problem, Level $$3-4$$, Question \#$$17$$) 

1) $$2$$ 
2) $$3$$ 
3) $$4$$ 
4) $$5$$ 
5) $$6$$ 