Dad bought 3.9 kilograms of apples. If he bought another 0.3 kilograms, it would be three times as much as his mother bought. How many kilograms of apples did they buy in total?
爸爸买了3.9千克的苹果，如果再多买0.3千克就相当于妈妈买的3倍，两人一共买了多少千克的苹果？
<gadget id="calculator">3.9 + 0.3</gadget>
<output>4.2</output>

<gadget id="calculator">4.2 / 3</gadget>
<output>1.4</output>

<gadget id="calculator">1.4 + 3.9</gadget>
<output>5.3</output>

<result>5.3</result>