/sci/ - Science & Math

Hey /sci/, I have a quick question that will probably get me laughed at, but I'd prefer a genuine answer because I'm not to keen on math, seeing as I stopped taking it in 9th grade.

So say there's a 25% chance of an event happening, but a safeguard with a 70% success rate is in place. On top of that, there is another safeguard with an 89% success rate active. What would be the chance of the event occurring?

I know you guys probably don't like answering questions like these but I'd too curious to not know.