12) Every hour Uncle Scrooge's wealth increases by 50%. If at 12 noon on a certain day Scrooge owns 64 fantabillion, what will his wealth be at 4 pm on the same day?
(A) 192 fantabillion
(B) 256 fantabillion,
(D) 486 fantabillion,
(E) 1024 fantabillion
(C) 324 fantabillion,
12. The answer is $(\mathbf{C})$.

Every hour, the value $P$ of Scrooge McDuck's fortune increases by $50 \%$. The value then becomes the previous value plus half of it. In other words, every hour the value of the fortune increases from $P$ to $P\left(1+\frac{1}{2}\right)=\frac{3}{2} P$. After the 4 hours that pass between 12 and 16, the fortune will be worth $\left(\frac{3}{2}\right)^{4}$ times its initial value, that is, $64 \cdot\left(\frac{3}{2}\right)^{4}=324$ fantabillions.