The weight of apples in basket A is three times that of basket B. If 20 kg of apples are taken from basket A and put into basket B, then the weights of the two baskets of apples are equal. How many kilograms of apples are there in basket B? (solution by equation)
甲筐苹果的重量是乙筐的3倍．如果从甲筐取出20千克放入乙筐，那么两筐苹果的重量就相等．乙筐原来有苹果多少千克？(用方程解)
<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<result>20</result>