In the green orchard, 2 kg of apples sell for 6 yuan, and 3 kg of bananas sell for 15 yuan. Teacher Zhang plans to buy 3 kilograms of apples and 4 kilograms of bananas, how much will it cost?
绿色果园2千克苹果售价6元，3千克香蕉售价15元．张老师打算买3千克苹果和4千克香蕉，需要多少钱？
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">15 / 3</gadget>
<output>5</output>

<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">9 + 20</gadget>
<output>29</output>

<result>29</result>