It costs 31.50 yuan to buy 3 kilograms of cabbage and 5 kilograms of eggplant. It is known that the price of cabbage per kilogram is 3.5 yuan. How much is eggplant per kilogram? (solution by equation)
买3千克白菜和5千克茄子共用了31.50元，已知每千克白菜的售价是3.5元，茄子每千克是多少元？(用方程解)
<gadget id="calculator">3 * 3.5</gadget>
<output>10.5</output>

<gadget id="calculator">31.5 - 10.5</gadget>
<output>21</output>

<gadget id="calculator">21 / 5</gadget>
<output>21/5 = around 4.2</output>

<result>21/5 = around 4.2</result>