The price ratio of two commodities, A and B, is 7:3. If their prices increase by 70 yuan respectively, then their price ratio is 7:4. What is the original price of commodity A?
甲乙两种商品的价格比是7：3，如果它们的价格分别上涨70元，那么它们的价格比是7：4．甲商品原来的价格是多少元．
<gadget id="calculator">7 / 4</gadget>
<output>7/4 = around 1.75</output>

<gadget id="calculator">(7/4) * 70</gadget>
<output>245/2 = around 122.5</output>

<gadget id="calculator">(245/2) - 70</gadget>
<output>105/2 = around 52.5</output>

<gadget id="calculator">(7/4) * 3</gadget>
<output>21/4 = around 5.25</output>

<gadget id="calculator">7 - (21/4)</gadget>
<output>7/4 = around 1.75</output>

<gadget id="calculator">(105/2) / (7/4)</gadget>
<output>30</output>

<gadget id="calculator">30 * 7</gadget>
<output>210</output>

<result>210</result>