Question

In a bag of marbles you have three green, two yellow, six blue, and nine red marbles. What is the probability of picking a red marble from the bag?

Answer 1

$|\Omega|=3+2+6+9=20-a\ number\ of\ all\ marables\\\\|R|=9-a\ number\ of\ red\ marables\\\\\boxed{P(R)=\dfrac{9}{20}}$