need help with a word problem

[jaayy513]

a jar contains 48 marbles, identical except for color. there are twice as many yellow as red marbles andtwice as many blue marbles as white marbles. what is the probability of drawing at random a yellow marble from the jar?

 

[Denis]

r = red marbles

draw yellow prob = r/24

 

[pka]

For example: r=1, y=2, w=15, & b=30 then P(y)=2/48.
On the other hand: r=15, y=30, w=1, & b=2 then P(y)=30/48.

So if r+y+b+w=48, y=2r and b=2w then r+w=16.
This means that 1≤w≤15, so that r=16−w.
So that y=2(16−w)=32−2w or P(y)=[32−2w]/48.

 

[stapel]

Without some relationship between the reds and yellows, on the one hand, and the whites and blues, on the other, I don't see any way of coming up with a numerical answer. Am I missing something?

Eliz.