Question

A bag has 5 red marbles, 6 blue marbles and 4 black marbles. What is the probability of picking a blue marble, replacing it, and then picking a black marble?

Answer 1

The probability of first picking a blue marble is given by:
\[P(blue)=\frac{number\ of\ blue\ marbles}{total\ number\ of\ marbles}=you\ can\ calculate\]
Similarly the probability of a black marble is:
\[P(black)=\frac{4}{15}\]
The required probability is given by:
\[P(blue) \times P(black)=you\ can\ calculate\]