Answer
(a) $0.17$
(b) $0.116$
(c) $0.067$
Work Step by Step
Use geometric formula with $p=1/6, q=5/6$
(a) win on his first purchase $P(1)=pq^0=1/6=0.17$
(b) win on his third purchase $P(3)=pq^2=0.116$
(c) not win on any of his first five purchases $P(6)=pq^5=0.067$
