MS if you've got it right you WILL KNOW IT with absolute certitude. Any doubts mean you haven't got it yet .
I quite like this kind of puzzle. I realised that it was going to be futile to spend time trying to 'work it out' so I did a Goole search of "what parking spot # is the car parked in" instead. It took a bit longer than 20 seconds but do I get any points for initiative...?? I'm not normally someone who cheats but its all about lateral thinking isn't it.
Took me a couple of minutes... took my 5th grade son 17 seconds. He guessed the right answer but he had difficulty explaining how he came to the right answer so I guess the answer really did come to him laterally!
Actually no, you obviously do not. Same for many posts here but I don't see anyone calling for a purging of this forum. Rorate speaks the truth most of the time, they just don't speak it with charity. I will pray for you all but I'm going to have to walk away from the toxic atmosphere of this forum. It has great potential but it eats its young.