A6. Let $\frac{a+b}{b}=4$. What is $\frac{b}{a+2b}$?
(A) 3
(B) 1
(C) 5
(D) $\frac{1}{3}$
(E) $\frac{1}{5}$

## II. PART
A6. From $\frac{a+b}{b}=4$ express $a=3b$ and substitute it into the fraction $\frac{b}{a+2b}$. Simplify and reduce the fraction to get the result $\frac{1}{5}$.

II. PART