ratio maths question

the question is
A tin contains red beads, white beads and blue beads in the ratio
red : white : blue = x : 2x : x2
13 (a) Show that the fraction of blue beads in the tin is x/x-3

now i know for ratios u add the numbers together and what not but i looked at the answer and it said this:

x^2/x2+2x+x which you simplify to get x/x-3

I just dont understand where the x^2 comes from

This might sound stupid and this is just a hunch, I'm not that good at Maths btw but could the x^2 refer to the number of blue beads since the fraction is basically (blue beads/all beads in the tin)?

oh ye could be
im actually stuck on this as well

The percentage of blue beads is 90%
Work out the value of x

i got to x=0.9x+2.7 but dont know what to do next :/

Woah, are this really GCSE maths questions? this is hard....

Anyway, the furthest I got was:

90%=X^2
10%=3x
3.33....%=x

Don't have the values though only percentage. Although, if you could subtitute numbers till you find the one, it could possibly work.

i get it now
ok so

x/x+3=0.9

x=0.9(x+3)
x= 0.9x+2.7
x-0.9x=2.7
factorise
x(1-0.9) = 2.7
x=2.7/(1-0.9)
x=2.7/0.1
x=27