Step 1: Problem
Step 2: Concept
![\text{Probability of any event = }\frac{n\text{ umber of required outcome}}{n\text{ umber of total possible outcome}}](https://img.qammunity.org/2023/formulas/mathematics/college/6loo7szb0ztqhfzwqv4akn5hk8mqkmi87x.png)
Step 3: Method
Red R = 3
Blue B = 2
Green G = 5
Total = 10
Apply tree diagram
Probability of choosing a red marble without replacement then a blue marble = Red, and Blue
'AND' in probability mean multiplication.
![\begin{gathered} =\text{ }\frac{3}{10\text{ }}\text{ x }(2)/(9) \\ =\text{ }(6)/(90) \\ =\text{ }(1)/(15) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/yr4zqgy06imkl7a1vall6f5mjf5zn39yol.png)
Step 4: Final answer
Probability of choosing a red marble without replacement then a blue marble = 1/15