Answer:
1/2
Step-by-step explanation:
Simple probability is a ratio of the number of ways the thing we want to happen can to the total possible outcomes.
(For example, we flip a coin and want heads, but it can land on heads or tails. Our probability of getting heads is 1/2, one way to get heads over the 2 possible outcomes)
So for this problem, there's 20 possible things that CAN happen (3 + 7 + 10) and 10 ways we get what we want (a green marble).
Our probability of getting a green marble is
, which simplifies to 

<em><u>Solution:</u></em>
Given that we have to find the value of "m"
Given expression is:

<em><u>Let us first convert the mixed fraction to improper fraction</u></em>
Steps to follow:
Divide the numerator by the denominator.
Write down the whole number answer.
Then write down any remainder above the denominator.
Therefore,

Now the expression becomes,

Keep the variable "m" on L.H.S and move the constant to R.H.S

Thus value of m is equal to 3.625 or 
142.8
it fizzes up and shoots out
88