In a building, the price per square meter of the third floor is 115% of the average price, and the price per square meter of the sixth floor is 75% of the average price. If the price per square meter of the sixth floor is 640 yuan less than that of the third floor, What is the average price of this building? Uncle Qian spent 120,000 yuan to buy a 100-square-meter building. Do you know which floor it is on?
一幢楼房，三楼每平方米的售价是平均价格的115%，六楼每平方米的售价是平均价格的75%，如果六楼每平方米的售价比三楼少640元，这幢楼房的平均价格是多少？钱叔叔花去12万买了一套100平方米的楼房，你知道在哪一层？
<gadget id="calculator">640 / 0.4</gadget>
<output>1_600</output>

<result>1_600</result>