Bamboozle is correct... they're not going to throw out something that isnt do-able in your head... or at least they didnt through my process
Now the mental maths on the computer tests at stage two whilst you're watching another part of the screen and have 2.6 seconds to answer... thats a bit diff
Basically its simple numbers. Forget physics or the term D/S/T if you want. Division and multiplication of what will usually be factors of 6 pretty much cover it
