To build two houses, the cost of the first house is 640,000 yuan less than three times the cost of the second house, and the cost of the second house accounts for (3/7) of the total cost of the two houses. The cost of the second house is How much is it?
建造两座房子，其中第一座造价比第二座造价的3倍少64万元，而第二座房子的造价占两座房子总造价的(3/7)，第二座房子的造价是多少万元？
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">3 * (3/7)</gadget>
<output>9/7 = around 1.285714</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">(9/7) - (4/7)</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">64 / (5/7)</gadget>
<output>448/5 = around 89.6</output>

<gadget id="calculator">(448/5) * (3/7)</gadget>
<output>192/5 = around 38.4</output>

<result>192/5 = around 38.4</result>