Reservoir A has 4.3 billion cubic meters of water, and Reservoir B has 3.7 billion cubic meters of water. May I ask: How many billion cubic meters of water need to be transferred from Reservoir A to Reservoir B so that the water in Reservoir B is twice as much as Reservoir A?
甲水库有43亿立方米水，乙水库有37亿立方米水．请问：需要从甲水库调多少亿立方米水到乙水库，才能使乙水库的水比甲水库多两倍？
<gadget id="calculator">43 + 37</gadget>
<output>80</output>

<gadget id="calculator">1 + 2 + 1</gadget>
<output>4</output>

<gadget id="calculator">80 / 4</gadget>
<output>20</output>

<gadget id="calculator">43 - 20</gadget>
<output>23</output>

<result>23</result>