If there are 3 green marbles in the urn, what is the probability of not getting a red marble?

Answer:
blue marble is 12/24
red marble is 9/24
green marble is 4/24
Step-by-step explanation:
since the equation said 12 blue marbles and It is one half it means that the original whole number of marbles is 24 so since the next one is 3/8 it means that 24 divide it by 8 then times it to three and you will get 9,and in the rest is 4 so yun ang green