There are three piles of black and white chess pieces, each pile has 30 pieces, the number of black stones in the first pile is the same as that of white stones in the second pile, and the black stones in the third pile account for (1/4) of all black stones. How many sunspots are there in these three piles of chess pieces?
有三堆黑白两色棋子，每堆棋子都是30枚，第一堆中的黑子和第二堆中的白子一样多，第三堆中的黑子占全部黑子的(1/4)．这三堆棋子中黑子一共有多少枚？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">30 / (3/4)</gadget>
<output>40</output>

<result>40</result>