There are three piles of chess pieces, the number of pieces in each pile is equal, the number of white pieces in the first pile is equal to the number of black pieces in the second pile, black pieces occupy (5/9) in the third pile, white pieces occupy the pieces in the three piles How much is the total.
有三堆棋子，每堆棋子的枚数相等，第一堆中的白棋与第二堆中的黑棋枚数相等，第三堆中黑棋占(5/9)，这三堆中白棋占棋子总数的多少．
<gadget id="calculator">13 / 27</gadget>
<output>13/27 = around 0.481481</output>

<result>13/27 = around 0.481481</result>