Seems to me as if it's just a quick way to gauge how ontheball and intelligent you are. I bet there were englishtype questions too.
Or I could be wrong. They could be silly. Yeah, it wasn't all maths. But you had to answer 10 out of 12, and there were enough of them that I couldn't answer, that it was either get them wrong and look stupid, or not send in the application at all.
I don't really have the experience to be a PA yet, so I probably wouldn't have got the job anyway. I just wish they wouldn't make things so difficult. I mean, I can count and I can use a calculator  why does it matter if I can't answer mental arithmetic questions on the fly? bloody hell.
maths is everywhere.
and i can't even count change to make up £1... i am doomed.  From:  tefkas 
Date:  September 20th, 2003  06:33 am 

   (Link) 

Your post kept me awake last night, pondering how to recreate the formula to calculate the sum 1 + 2 + 3 + ... + n
Eventually, I scribbled it out to ½n(n+1)
So, the sum of all the numbers, 1 to 99 is ½ x 99 x 100 = ½ x 9,900 = 4,950
I even have a cool, diagramatic (rather than algebraic) proof to demonstrate why, but I doubt you'd find such rivetting.
Anyway, the point being that when I read your post, I knew it could be calculated simply, but couldn't remember how... and I have a degree in maths!
And then I couldn't get any sleep until I'd worked it out. 