החיים האלטרנטיביים שלי

Introduction

By now I noticed that mathematical riddles and logic riddles are a big thing here, might even get me popular.And since popularity is all I am asking for I decided to follow Alice's lead.

Now I gonna ask some four (currently that might be more) mathematical riddles in the next few days. A prize will be given to one of the persons who will answer all the riddles correctly. Unlike previous occasions, pinxasa is not eligale to win the prize nor any of my other identities here. There will be a prize.

and once I am next to a hebrew computer these riddles will be translated to hebrew. the answer to all of them will be given at the end of the contest with the name of the winner. 

and now for riddle a.

The way to Oslo

If a two hours drive distance to Oslo took me four hours, and one hour drive distance to Oslo took me two hours, how many hours was I driving to Oslo?

Instruction:

you should input in your calculation the fact that I had to stop for shopping in this route since Sweden is much more cheaper than Norway, and I was coming from Sweden.