There is a group of computers in the computer city, 60% of the total number are sold, and another 192 sets are shipped in. At this time, the ratio of the number of computers in the computer city to the original number is 6:7. How many original computers are there in the computer city?
电脑城里有一掇电脑，卖出总数的60%，又运来192台，这时电脑城的电脑台数与原来台数的比是6：7．电脑城里原有电脑多少台？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">1 - (6/7)</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(3/5) - (1/7)</gadget>
<output>16/35 = around 0.457143</output>

<gadget id="calculator">192 / (16/35)</gadget>
<output>420</output>

<result>420</result>