Question

Two marbles are drawn without replacement from a box with 3 white, 2 green, 2 red, and 1 blue marble, find the probability that the 1st marble is red and the second marble is green

Answer 1

The total number of marbles is $3+2+2+1=8$.

If we draw a red marble, the chance of that occurring is $\frac{2}{8}=\frac{1}{4}=0.25$.

Now the total number of marbles left is 7. If we then draw a green marble, the chance of that occurring is $\frac{2}{7}\approx 0.29$.

So the chance of drawing a red, then green, marble is $\frac{1}{4}*\frac{2}{7}=\frac{2}{28}=\frac{1}{14}\approx 0.07$.