A bag initially contains red marbles and blue marbles only, with more blue than red. Red marbles are added to the bag until only 1/3 of the marbles in the bag are blue. Then yellow marbles are added to the bag until only 1/5 of the marbles in the bag are blue. Finally, the number of blue marbles in the bag is doubled. What fraction of the marbles now in the bag are blue?
<spanclass=′latex−bold′>(A)</span>51<spanclass=′latex−bold′>(B)</span>41<spanclass=′latex−bold′>(C)</span>31<spanclass=′latex−bold′>(D)</span>52<spanclass=′latex−bold′>(E)</span>21