ZIO 2015 and ZIO 2014 doubt!

general
1

How do we solve the last question of ZIO 2014 and ZIO 2015.(Question 4 of each)
Links-

2104

2015

Please give the answers along with the explanations and proofs.

2

Hi

You can find ZIO 2014 and 2015 solutions here …

link text

link text

Happy Coding …

3

I know I can find the answers but I want the explanation and proof as I said in the question.