I have tried this problem a few times, and don't feel confident about my answer.

Here's the Question:

A financial company prepares tax returns for individuals. According to IRS, individuals in a certain high income bracket are audited at a rate of 1.5%. The company prepares 5 tax returns for individuals in that high tax bracket. Find the probability that at least 3 are audited.

My work:

n=5

x=greaterthan or equal to 3

p=.015

q=.985

5C3 (.015)^3(.985)^2 + 5C4 (.015)^4(.985)^1 + 5C5 (.015)^5(.985)^0

= 10 (.00000328) + 5 (.0000000497) + 1 (.000000000759)

= .0000328 + .000000249 + .000000000759

= .0000329951

Basically, I don't feel confident in my answer. Any feedback is good feedback to me. Thanks!