2014 Fermat Problem 21

A bin contains 10 kg of peanuts. 2 kg of peanuts are removed and 2 kg of raisins are added and thoroughly mixed in. Then 2 kg of this mixture are removed and 2 kg of raisins are added and thoroughly mixed in again. What is the ratio of the mass of peanuts to the mass of raisins in the final mixture?

\textbf{(A)}\ 3:2\quad \textbf{(B)}\ 4:1\quad \textbf{(C)}\ 5:1\quad \textbf{(D)}\ 7:3\quad \textbf{(E)}\ 16:9

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Full credit to this problem is given to the CEMC, you may view all Fermat contests here.