Math Help - Continuity problem

1. Continuity problem

how do i do this problem?
Try to use this : if $a_1,a_2\ldots a_n$ are $n$ real numbers then $\min_{1\leq i\leq n}a_i\leq \frac{a_1+a_2+\cdots+a_n}{n}\leq \max_{1\leq i\leq n}a_i$.