Question 28
Which of the following is satisfied by all numbers $x$ of the form $$
x=\frac{a_1}{3}+\frac{a_2}{3^2}+\cdots+\frac{a_{25}}{3^{25}},
$$ where $a_1$ is $0$ or $2,$ $a_2$ is $0$ or $2,$ $\ldots,$ $a_{25}$ is $0$ or $2?$
x=\frac{a_1}{3}+\frac{a_2}{3^2}+\cdots+\frac{a_{25}}{3^{25}},
$$ where $a_1$ is $0$ or $2,$ $a_2$ is $0$ or $2,$ $\ldots,$ $a_{25}$ is $0$ or $2?$