The pears in the fruit shop are 7.8 yuan per kilogram, and the apples are 8.2 yuan per kilogram. Wang Gang bought 3 kilograms of pears and 5 kilograms of apples. Please ask a mathematical question and answer it.
水果店里的梨每千克7.8元，苹果每千克8.2元．王刚买了3千克梨和5千克苹果．请你提出一个数学问题，并解答．
<gadget id="calculator">7.8 * 3</gadget>
<output>23.4</output>

<gadget id="calculator">8.2 * 5</gadget>
<output>41</output>

<gadget id="calculator">23.4 + 41</gadget>
<output>64.4</output>

<result>64.4</result>