Mom went to the supermarket to buy vegetables. It cost 1 yuan and 50 cents to buy 500 grams of cucumbers, and 4 yuan and 20 cents to buy 3 kilograms of radishes. Which dish is more expensive? How much is it per kilogram?
妈妈到超市买菜，买500克黄瓜花了1元5角，买3千克萝卜花了4元2角．哪种菜贵些？每千克贵多少元？
<gadget id="calculator">500 / 1_000</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">15 / 10 / (1/2)</gadget>
<output>3</output>

<gadget id="calculator">42 / 10 / 3</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">3 - (7/5)</gadget>
<output>8/5 = around 1.6</output>

<result>8/5 = around 1.6</result>