Question
PSLE
A box contained blue marbles and brown marbles. 60% of the marbles were brown. After some black marbles were added to the box, 9% of the marbles were brown. What percentage of the marbles in the box were black?
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PSLE
A box contained blue marbles and brown marbles. 60% of the marbles were brown. After some black marbles were added to the box, 9% of the marbles were brown. What percentage of the marbles in the box were black?