Question

Emma selects markers from a bag without looking at them. The bag has 8 green markers, 4 red markers, and 3 blue markers. What is the probability that she selects a red, does not replace it and then selects a blue marker.

Answer 1

$\dfrac{3}{14}$

Step-by-step explanation:

Given,number of red markers=$n_{r}$=4

number of green markers=$n_{g}$=8

number of blue markers=$n_{b}$=3

$probability=\frac{\text{number of favourable outcomes}}{\text{total number of outcomes} }$

Let $p_{1}$ be the probability of getting a red marker=$\frac{\text{number of red markers}}{\text{total number of markers}}$

So,$p_{1}$=$\frac{4}{8+4+3}=\frac{4}{15}$

Let $p_{2}$ be the probability of getting a blue marker after getting a red marker.

After removing a red marker,$n_{r}$ becomes 3 and $n_{g},n_{b}$ remain same.

$p_{2}=$$\frac{3}{8+4+3}=\frac{3}{14}$

Probability for getting a red marker followed by getting a blue marker is $p_{1}\times p_{2}=\frac{4}{15}\times \frac{3}{14}=\frac{2}{35}$