So since there are 6 blue marbles, 10 red marbles, and 9 green marbles, that means that there are 25 marbles in total. This means the chance of pulling ONE red marble is 10/25 which simplifies to 2/5. If you want to pull 2 red marbles, you'd multiply the chance of pulling one marble to the chance of pulling one marble. (2/5 times 2/5)
You'd get 4/10. Which is a 40% percent chance.
(not completely sure about this one..)
