Mom bought apples and pears for a total of 17.4 yuan, pears were 1.8 yuan per kilogram, and apples were 2.4 yuan per kilogram. She bought 3 kilograms of pears and asked how many kilograms of apples she bought.
妈妈买苹果和梨共花了17.4元，梨每千克1.8元，苹果每千克2.4元，买了3千克梨，问买了多少千克苹果．
<gadget id="calculator">1.8 * 3</gadget>
<output>5.4</output>

<gadget id="calculator">17.4 - 5.4</gadget>
<output>12</output>

<gadget id="calculator">12 / 2.4</gadget>
<output>5</output>

<result>5</result>