答案:(a) $x=6$, $y=22$, $z=40$ (b) $\dfrac{2}{5}$
- 透過比較兩個表的第一行,可得 $a=2$.
$\begin{array}{rcl}
x & = & a + 4 \\
x & = & 2 + 4 \\
x & = & 6
\end{array}$$\begin{array}{rcl}
b & = & 13 – x \\
b & = & 13 – 6 \\
b & = & 7
\end{array}$$\begin{array}{rcl}
z & = & 37 + 3 \\
z & = & 40
\end{array}$$\begin{array}{rcl}
c & = & 40 – 3 – 15 – 7 – 4 – 2 \\
c & = & 9
\end{array}$$\begin{array}{rcl}
y & = & 13 + c \\
y & = & 13 + 9 \\
y & = & 22
\end{array}$所以,$x=6$、$y=22$ 及 $z=40$。
- $P\text{(選出的植物的高度少於 $1.25$ m 但不少於 $0.65$ m)}$
$\begin{array}{cl}
= & \dfrac{22 – 6}{40} \\
= & \dfrac{2}{5}
\end{array}$