(If I can)
a -------b ---------c
For arguments sake let's pretend that that is a line.
So if the ratio of vector ab:vector bc was 1:3 ... Imagine it like a cake and think how much each person gets and the total number of slices. So ab would get one slice. And bc would get three. And total four slices.
Then let's pretend the vector ab is of magnitude 5. So vector bc would be 15 as there are three 'lots' of ab. Vector ac is of magnitude 20.
Not sure if that made a lot of sense. I think I might have confused myself as well.
What I really find hard is Questions about
* doing substitution method
* and drawing tree probability diagram
I have done the 2013 season Paper calculator as revision and got 77/100
As well as doing the Non-calculator paper.
If you have any help full website please tell me.
E.g. shop A --> shop B --> shop C
AB:BC is split in the ratio 1:2 and the total distance AC is 9km.
So you add up the ratio which = 3.
Then divide 9 by 3 (9/3), which will give you 3
(1x3) : (2x3).
Therefore the ratio of AB:BC is 3:6.
Hope that helps