$17 \cdot 138$ Nine lines parallel to the base of a triangle divide the other sides into 10 equal segments, and at the same time divide the area into 10 different parts. If the largest area among these parts is 38, then the area of the original triangle is
(A) 180.
(B) 190.
(C) 200.
(D) 210.
(E) 240.
(22nd American High School Mathematics Examination, 1971)
[Solution] Let $b$ and $h$ represent the lengths of the base and height, respectively, because

that is
$$
\begin{array}{c}
38=\frac{1}{2}(b+0.9 b) \cdot 0.1 h, \\
-\frac{1}{2} \cdot 0.19 b h=38, \\
S_{\triangle}=\frac{1}{2} b h=\frac{38}{0.19}=200 .
\end{array}
$$

Therefore, the answer is $(C)$.