# Suppose you choose marble from a bag containing 2 red marbles, 5 white marbles, and 3 blue marbles. You return the first marble to the bag and choose again. How do you find P(red then blue)?

##### 1 Answer

$\frac{1}{10}$

#### Explanation:

There are 10 marbles. The probability of drawing a red is $\frac{2}{10} = \frac{1}{5}$, white is $\frac{5}{10} = \frac{1}{2}$ and blue is $\frac{3}{10}$.

I can then say the probability of drawing a red, replacing it, and then a blue is:

$P \left(\text{drawing red then blue, with replacement}\right) = \frac{1}{5} \times \frac{1}{2} = \frac{1}{10}$