\textbf{114.} There are 24 grams of a radioactive element. If $\dfrac{1}{10}$ of the element decays every 30 days, after how many days will 8 grams remain? $(\log 3 = 0.48)$
$$360 \quad (1) \qquad 300 \quad (2) \qquad 270 \quad (3) \qquad 240 \quad (4)$$