Question

What is the probability that Glenn will get a yellow marble

Answer 1

The bag has 5 marbles

3 yellow marbles

2 red marbles

"Glen chooses a marble first and then Kris chooses one" You have to determine the probability of Kris choosing a yellow marble if Glen chooses a yellow one first.

1. First you have to determine the probability that Glen choose a yellow marble first.

To do so, you have to calculate the quotient between the number of yellow marbles on the bag and the total number of marbles on the bag:

`\begin{gathered} P(Y_1)=\frac{nº\text{yellow}}{\text{total}} \\ P(Y_1)=(3)/(5) \end{gathered}`

2. and 3.

After Glen takes the first yellow marble from the bag, the total number of marbles is reduced by one and so is the number of yellow marbles on the bag, so:

New total: 4 marbles

Number of yellow marbles: 2

4.

To determine the probability of Kris choosing a yellow marble, you have to use the data on the remaining marbles on the bag. And calculate the quotient between the remaining number of yellow marbles and the remaining number of marbles:

`\begin{gathered} P(Y_2)=(2)/(4) \\ P(Y_2)=(1)/(2) \end{gathered}`