There are three containers $$A$$, $$B$$, and $$C$$. Each container has $$30$$ grams, $$40$$ grams, and $$50$$ grams of pure water respectively. Now we put $$10$$ grams of solution of a certain concentration into container $$A$$, then put $$10$$ grams of solution from container $$A$$ into container $$B$$, finally put $$10$$ grams of solution from container $$B$$ into container $$C$$. Given that the final concentration in container $$C$$ is $$0.5 \%$$, what was the concentration of the solution that we put into container $$A$$ originally? 
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