If $\frac{a}{3}=\frac{b}{2}=\frac{c}{1}$, then $\frac{a+b+2c}{b}$ is

1. Set the ratios equal to a constant $k$:
$$\frac{a}{3}=\frac{b}{2}=\frac{c}{1}=k$$
This gives $a=3k$, $b=2k$, and $c=1k$.Substitute these values into the given expression:
$$\frac{a+b+2c}{b}=\frac{3k+2k+2(1k)}{2k}$$
$$\frac{a+b+2c}{b}=\frac{3k+2k+2k}{2k}=\frac{7k}{2k}=\frac{7}{2}=3.5$$