To solve this, we use the binomial probability equation:
P = [n! / (n – r)! r!] * p^r * q^(n – r)
where n is the total number of days = 5, r is number of days he get stopped = 0, p is probability he gets stopped = 0.15, q is 1 – p = 0.85
P = [5! / (5 – 0)! 0!] * 0.15^0 * 0.85^(5 – 0)
P = 0.4437
Hence about 44.37% he does not get stop at all.