Question

if a bag contains 2 red marbles, 3 blue marbles, 5 yellow marbles and 2 green marbles, if a marble is randomly selected what is the probability that it is red _______

Answer 1

So red, blue, yellow, green

2 red
3 blue
5 yellow
2 green

probability= $\frac{desired outcomes}{total possible outcomes}$

the desired outcomes is red or 2

total possible is all marbles or 2+3+5+2=12

so the probability of picking a red marble is 2/12=1/6

Answer 2

All you need to do here is just find the ratio of red marbles to all of the marbles.
                    2 red                       
2 red + 3 blue + 5 yellow + 2 green

when you add everything up, you get 2/12, which is equal to 1/6.