probability::tree diagram ::argent H.W

**John tries to repair a broken toy.Each time he tries the probability that he succeeds is 0.8 .Each time he fails he tries again...**

**(a) **__Copy and complete the tree diagram below:__

**1st try**

0.8 ــــــــــــــ succeeds

0.2 ــــــــــــــ fails

**2nd try**

.... ــــــــــــــ succeeds

.... ــــــــــــــ fails

**3rd try**

.... ــــــــــــــ succeeds

.... ــــــــــــــ fails

**(b) **__Find the probability that, to succeed, it takes __

(i) exactly two tries,

(ii) one,two or three tries,

(iii) exactly five tries

**(c) Write down a formula for the probability that he has not succeeded after ****n** **tries.**

------------------

plz help me in these problem

and i wanna da answer with da steps plz......