A certain plant grows from germination to growth. If the height of a plant grows twice that of the previous day, it will grow to 20 cm after 6 days. Then when it grows to the first few days, it will be 160 cm.
某植物从发芽到长大，如果每天长的高度是前一天的一倍，经过6天长到20厘米．则当它长到第多少天完是160厘米．
<gadget id="calculator">6 + 3</gadget>
<output>9</output>

<result>9</result>