Question 26
Let $x_1, x_2, \dots, x_9$ be non-negative real numbers such that
$$
x_1^2 + x_2^2 + \dots + x_9^2 \geq 25
$$
*Prove that there are three of these numbers whose sum is at least 5.*
$$
x_1^2 + x_2^2 + \dots + x_9^2 \geq 25
$$
*Prove that there are three of these numbers whose sum is at least 5.*