probobility of a tax inspecton

#1
From our statistics the probability of getting an inspection in any single week is a pprox 1,000 : 1

I was trying to work out the probability over 6 years ie 300 weeks i tried binomial formula and got 27% but is this 1 success only ? what if i want at least 1 success what is the result?

Thank you
 

Dason

Ambassador to the humans
#2
A few questions that might help... If you know the probability of an event what can you say about the probability of the event not occurring? What would it mean for "at least one success" to not occur?