A pile of briquettes was transported, all (3/8) was delivered the first time, and 50 yuan was delivered the second time. At this time, the ones that have been delivered happened to be the ones that were not delivered (5/7). How many pieces of briquettes are there in total?
运一堆蜂窝煤，第一次运来了全部的(3/8)，第二次50块，这时，已运来的恰好是没运来的(5/7)，一共有多少块蜂窝煤？
<gadget id="calculator">5 + 7</gadget>
<output>12</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">12 * (3/8)</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">5 - (9/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">50 / (1/2)</gadget>
<output>100</output>

<gadget id="calculator">100 * 12</gadget>
<output>1_200</output>

<result>1_200</result>