# Monotone and bounded sequence

Let (xn) be a seq of real nos and let sn = x1+x2+x3+...+xn / n.

prove that if if xn is bounded and monotone, then sn is also bdd and monotone.

I got it in the test today and i couldn't figure it out. only hint i could think of is how do i prove if xn is increasing because if i prove tht i can prove it. but i could not do it