If $800670=8 \times 10^{x}+6 \times 10^{y}+7 \times 10^{z}$, where $x, y$ and $z$ are whole numbers, then $x+y+z$ equals
(A) 11
(B) 8
(C) 6
(D) 3
(E) 5
Rewriting the given integer,

$$
800670=800000+600+70=8 \times 10^{5}+6 \times 10^{2}+7 \times 10^{1}
$$

so $x=5, y=2$ and $z=1$, which gives $x+y+z=8$.

Answer: (B)