A traveler spends half of his money and one crown every day; his money ran out in three days. How much money did he have?
If on the third day he still had $x$ coronas, then after spending half of his money, 1 corona remained; thus

$$
\frac{x}{2}=1, \quad x=2
$$

on the second day he had: $(2+1) \times 2=6$, and on the first day he had: $(6+1) \times 2=14$.

(Pál Ligeti, Budapest.)