2 out of 30 items are charges wrong when checking out at a grocery store

if I purchase 12 items what is the probability that I will not be charged incorrecyly?

the answer is .4370

I am a math tutor and having trouble with this one ---- help

You've asked this same question now three separate times - please stop repeating it. Your question was answered here:

https://www.askmehelpdesk.com/mathematics/probability-758470.html