Xiaoqiao's mother brought 58 yuan and bought pears at 2.8 yuan per kilogram. The recovered money happened to buy 6 small bowls with a unit price of 6.4 yuan. How many kilograms of pears did my mother buy?
小巧妈妈带了58元，买了每千克2.8元的梨．找回的钱正好买6个单价为6.4元的小碗．妈妈买了多少千克的梨？
<gadget id="calculator">6.4 * 6</gadget>
<output>38.4</output>

<gadget id="calculator">58 - 38.4</gadget>
<output>19.6</output>

<gadget id="calculator">19.6 / 2.8</gadget>
<output>7</output>

<result>7</result>