2017-II-11

Ans: B
The length in map $:$ the actual length

$\begin{array}{cl}
= & 1 : 20\ 000 \\
= & 1 \text{ cm} : 20\ 000 \text{ cm}
\end{array}$

Hence, the area in the map $:$ the actual area

$\begin{array}{cl}
= & 1 \text{ cm}^2 : 20\ 000^2 \text{ cm}^2 \\
= & 1 \text{ cm}^2 : 400\ 000\ 000 \text{ cm}^2 \\
= & 4 \text{ cm}^2 : 1\ 600\ 000\ 000 \text{ cm}^2 \\
= & 4 \text{ cm}^2 : 160\ 000 \text{ m}^2 \\
= & 4 \text{ cm}^2 : 1.6 \times 10^5 \text{ m}^2
\end{array}$

Therefore, the actual area of the zoo is $1.6 \times 10^5 \text{ m}^2$.