Question

A bag of marbles has 3 red, 4 blue, and 5 white marbles in it. What is the probability of reaching in and selecting a blue marble? (without looking)

Answer 1

Answer:

$P(B)=\frac{1}{3}$

Step-by-step explanation:

The number of red marbles in the bag is; $n(R)=3$.

The number of blue marbles in the bag is; $n(B)=4$.

The number of white marbles in the bag is; $n(W)=5$.

The total number of marbles in the bag is: $n(S)=3+4+5=12$.

The probability of selecting a blue marble is $P(B)=\frac{n(B)}{n(S)}$

We substitute the given information to obtain:

$P(B)=\frac{4}{12}$

We simplify to obtain:

$P(B)=\frac{1}{3}$