There are four piles of coal, A, B, C, and D. The weight of A is (1/3) that of the other three piles, the weight of B is less than that of A (1/5), and the ratio of the weight of C to the other three piles is 1:5, the weight of D is 46 piles, find the weight of pile A.
有甲、乙、丙、丁四堆煤，甲的重量是其它三堆重量的(1/3)，乙的重量比甲的重量少(1/5)，丙与其它三堆重量之比为1：5，丁的重量为46堆，求甲堆的重量．
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/4) * (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + 5</gadget>
<output>6</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/4) - (1/5) - (1/6)</gadget>
<output>23/60 = around 0.383333</output>

<gadget id="calculator">46 / (23/60)</gadget>
<output>120</output>

<gadget id="calculator">120 * (1/4)</gadget>
<output>30</output>

<result>30</result>