The price ratio of A and B is 3:5. If the price of A increases by 20 yuan and the price of B decreases by 20 yuan, the price ratio of A and B is 5:7. How much is the original price of commodity A?
甲、乙两件商品的价格比是3：5，如果甲商品提价20元，乙商品降价20元，则甲、乙两件商品的价格比是5：7．问原来甲商品的价格是多少元？
<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(5/7) * 20</gadget>
<output>100/7 = around 14.285714</output>

<gadget id="calculator">20 + (100/7)</gadget>
<output>240/7 = around 34.285714</output>

<gadget id="calculator">5 / 3</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">(5/7) * (5/3)</gadget>
<output>25/21 = around 1.190476</output>

<gadget id="calculator">(25/21) - 1</gadget>
<output>4/21 = around 0.190476</output>

<gadget id="calculator">(240/7) / (4/21)</gadget>
<output>180</output>

<result>180</result>