Question (3): As shown in Figure 3, if $F D$ is connected, what is the probability that it reaches $D$?

 untranslated part: 

(3) : 如图 3 所示, 如果 $F D$ 是相连的, 它色到 $D$处的概率是多少? 

translated part:

(3): As shown in Figure 3, if $F D$ is connected, what is the probability that it reaches $D$?
Solve: The probability that it slinks to $D$ is $\frac{1}{2} \times \frac{1}{4}+\frac{1}{2} \times \frac{1}{2}=\frac{3}{8}$.