Question 68858
The chances of choosing a green marble is represented by the number of green marbles divided by the total number of marbles. To find the probability of finding the orange is again number of orange over total, which is now minus one. 

Here is a symbolic representation:

P(choosing green)=#green marbles/#total
P(choosing orange)=#orange marbles/#total

In this case:

P(green)={{{5/(5+3)=5/8}}}
P(orange)={{{3/(5+3-1)=3/7}}}

which makes sense, the more green means there's a higher chance of picking them