Ans: (a) $450$ (b) (i) $80\%$ (ii) $80$
- The number of girls in the school
$\begin{array}{cl}
= & 625 \times (1- 28\%) \\
= & 450
\end{array}$ -
- Total number of students in the school
$\begin{array}{cl}
= & 625 + 450 \\
= & 1075
\end{array}$Therefore, the percentage of local students in the school
$\begin{array}{cl}
= & \dfrac{860}{1075} \times 100\% \\
= & 80\%
\end{array}$ - Since the percentage of local students in the school is $80\%$ and there are $80\%$ of the boys are local, then there must be $80\%$ girls are also local. Hence, $x=80$.
- Total number of students in the school