Three people, A, B, and C, each have a certain number of items, and exchange them with each other. First, B takes out (1/3), and C takes out (1/10) and gives them to A, and then A takes out (1/8). Take out (1/9) from C and give to B, and finally take out (3/11) from B, and give to C from A (2/7). At this time, A has 155, B has 136, and C has 209 , Find how many A there are at the beginning.
甲、乙、丙三人，各有某种物品若干，互相交换，先由乙取出(1/3)，由丙取出(1/10)都给甲，再由甲取出(1/8)，由丙取出(1/9)都给乙，最后由乙取出(3/11)，由甲取出(2/7)都给丙，这时甲有155个，乙有136个，丙有209个，求开始时甲有多少个．
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 - (2/7)</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">155 / (5/7)</gadget>
<output>217</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 - (1/8)</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">217 / (7/8)</gadget>
<output>248</output>

<gadget id="calculator">3 / 11</gadget>
<output>3/11 = around 0.272727</output>

<gadget id="calculator">1 - (3/11)</gadget>
<output>8/11 = around 0.727273</output>

<gadget id="calculator">136 / (8/11)</gadget>
<output>187</output>

<gadget id="calculator">248 * (1/8)</gadget>
<output>31</output>

<gadget id="calculator">217 * (2/7)</gadget>
<output>62</output>

<gadget id="calculator">187 * (3/11)</gadget>
<output>51</output>

<gadget id="calculator">209 - 62 - 51</gadget>
<output>96</output>

<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">1 - (1/9)</gadget>
<output>8/9 = around 0.888889</output>

<gadget id="calculator">96 / (8/9)</gadget>
<output>108</output>

<gadget id="calculator">108 * (1/9)</gadget>
<output>12</output>

<gadget id="calculator">187 - 31 - 12</gadget>
<output>144</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">144 / (2/3)</gadget>
<output>216</output>

<gadget id="calculator">216 * (1/3)</gadget>
<output>72</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">108 / (9/10)</gadget>
<output>120</output>

<gadget id="calculator">120 * (1/10)</gadget>
<output>12</output>

<gadget id="calculator">248 - 72 - 12</gadget>
<output>164</output>

<result>164</result>