The answer depends on how many marbles are picked and on whether or not they are returned to the jar before picking the next one. Since you have not bothered to provide any information on either of these aspects, I cannot provide a more useful answer.
It is 3/5.
The probability of picking a green marble from a box that only contains blue marbles is zero.
The probability, in one draw, is 6/20 or 30%
Probability of drawing a red marble = 4/16 = 1/4 Probability of drawing not a red marble = 1 - 1/4 = 3/4
if you pick one marble at random, the odds are 17/(42+17+27) or 17/86 or about 20%
1/2
The probability of picking a green marble from a box that only contains blue marbles is zero.
1 in 7
There is a one in 2 chance of getting a green marble.
The probability, in one draw, is 6/20 or 30%
Probability of drawing a red marble = 4/16 = 1/4 Probability of drawing not a red marble = 1 - 1/4 = 3/4
if you pick one marble at random, the odds are 17/(42+17+27) or 17/86 or about 20%
1/2
25/50 gives the probability of selecting a blue marble
0No blue marbles in the bag.
your probability would be 13/13. you would have a 100 percent chance of getting a green marble
5:16
There is a probability of 3 that it will be blue.