Drawing Odds Calculation Question

[COSA]

For all you math gurus, it's been a long time since I took statistics:
Say you put in for 5 tags in a given year, with a 5% chance of drawing each individual tag - how would you calculate the odds of drawing any of those tags?
My "easy" button says to sum them up (25%), though I don't think this is correct (if you put in for 20 tags at 5% you still would not be guaranteed a tag). Thanks.

 

[efnm]

You need to determine the probability of NONE of the events happening and then subtract that from 1.

So, the odds of not getting that first tag is 95%, but the odds not getting any of those 5 tags is .95*.95*.95*.95*.95 = .774.

Therefore, your odds of getting at least one is 1-.774 = 22.6%

 

[COSA]

Perfect - thanks.