18% of lamps are left "On" on any given night.

Suppose that, one night, 16 lamps are randomly selected for examination.

What is the probability that 4 or more of the examined lamps are "On"?

Hi... I need help solving this basic probability question, lol. I use to be good with this kind of thing, but I've forgotten how its done and I'm trying to refresh myself :\.

Any help would be appreciated :).