A strange plant has been cultivated in the laboratory. It grows very rapidly, and every day it grows to twice the mass of yesterday, which is more than 3 kilograms. After cultivating for 3 days, the mass of the plant reaches 45 kg. How many kg does this plant originally weigh?
实验室中培养了一种奇特的植物，它生长得非常迅速，每天都会生长到昨天质量的2倍还多3公斤．培养了3天后，植物的质量达到45公斤，求这株植物原来有多少公斤？
<gadget id="calculator">2 * 2 * 3</gadget>
<output>12</output>

<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<gadget id="calculator">45 - 12 - 6 - 3</gadget>
<output>24</output>

<gadget id="calculator">2 * 2 * 2</gadget>
<output>8</output>

<gadget id="calculator">24 / 8</gadget>
<output>3</output>

<result>3</result>