maths question

hi, please could i have some help on part b of this question: https://www.youtube.com/watch?v=9MmIne-qf2Q
i sort of understand what is he is saying but I'm confused about the probabilities he wrote in the table? If there is m lots of 2 and 1 lot of n for example, shouldn't the probability be (1/4)^m*2/3 because you need m lots of 2 so it would be 1/4*1/4*...
thanks!

R and G represent spnning each spinner once so the new score X
X = mR + nG
is the weighted (by integers m and n) score of spinning red once (R) and geeen once (G). The fact you have 20 and 50 is because of the weighting integers m and n which you need to find.

Sorry what do you mean by weighting? Does m not mean R was spun that many times?

No, its just a multiplier. In the question you asked rufus yeserday you had
X + 2Y
so X and Y are random variables and you multiply the Y value by 2 (and add to X). Here youve two (unknown) integers m and n and you do
mR + nG
to get a new random variable / score and you have to determine m and n.