Geometry

Question Analysis
This basic conditional probability problem focuses on sequential events without replacement.
The main concept is how the first event affects the probability of the second event.

Key Concept Explanation
Initial State: 4 red + 6 blue = 10 marbles
After First Pick: If first marble was red, remaining marbles are 3 red + 6 blue
Conditional Probability: Probability is calculated based on the new sample space

Step-by-Step Solution
First pick: Red marble (given)
Remaining marbles: 3 red + 6 blue = 9...