Mom went to the supermarket to buy vegetables. She bought 2.5 kilograms of tomatoes and 4 kilograms of cucumbers. She paid a total of 26.5 yuan. Tomatoes were 5.4 yuan per kilogram. How much did you spend on cucumbers?
妈妈到超市买菜，买了2.5千克西红柿，4千克黄瓜，共付了26.5元，西红柿每千克5.4元，买黄瓜花了多少钱？
<gadget id="calculator">5.4 * 2.5</gadget>
<output>13.5</output>

<gadget id="calculator">26.5 - 13.5</gadget>
<output>13</output>

<result>13</result>