A law enforcement agency processes 500 background checks for firearms purchasers ...

  

A law enforcement agency processes 500 background checks for firearms purchasers. Fifty applicants are convicted felons. Through a clerk's error, ten applicants are approved without checking for felony convictions.

a What is the probability that none of the 10 is a felon?

b That at least two of the 10 are convicted felons?

c That fewer than 4 of ten are convicted felons?

d Justify the use of the binomial approximation.