Math Problem Statement

A jar contains 5 red marbles, 2 white marbles, and 3 blue marbles. Two marbles are randomly selected from the jar with replacement. Find the following probabilities. Leave your answer as a reduced fraction. A red marble and then a blue marble is randomly selected.

A white marble and then a red marble is randomly selected.

Solution

We can solve this using basic probability rules. Since the marbles are drawn with replacement, the probability for each draw remains unchanged.

Total Marbles in the Jar:

The jar contains:

  • 5 red marbles
  • 2 white marbles
  • 3 blue marbles

So, the total number of marbles is: 5+2+3=10 marbles.5 + 2 + 3 = 10 \text{ marbles}.

1. Probability of selecting a red marble and then a blue marble:

The probability of selecting a red marble on the first draw: P(Red)=510=12.P(\text{Red}) = \frac{5}{10} = \frac{1}{2}.

The probability of selecting a blue marble on the second draw (since the total number of marbles stays the same due to replacement): P(Blue)=310.P(\text{Blue}) = \frac{3}{10}.

Now, using the multiplication rule for independent events, the probability of selecting a red marble followed by a blue marble is: P(Red and Blue)=P(Red)×P(Blue)=12×310=320.P(\text{Red and Blue}) = P(\text{Red}) \times P(\text{Blue}) = \frac{1}{2} \times \frac{3}{10} = \frac{3}{20}.

2. Probability of selecting a white marble and then a red marble:

The probability of selecting a white marble on the first draw: P(White)=210=15.P(\text{White}) = \frac{2}{10} = \frac{1}{5}.

The probability of selecting a red marble on the second draw: P(Red)=510=12.P(\text{Red}) = \frac{5}{10} = \frac{1}{2}.

Now, the probability of selecting a white marble followed by a red marble is: P(White and Red)=P(White)×P(Red)=15×12=110.P(\text{White and Red}) = P(\text{White}) \times P(\text{Red}) = \frac{1}{5} \times \frac{1}{2} = \frac{1}{10}.

Final Answers:

  1. The probability of selecting a red marble and then a blue marble is 320\frac{3}{20}.
  2. The probability of selecting a white marble and then a red marble is 110\frac{1}{10}.

Would you like more details or have any questions?

Here are 5 related questions:

  1. What is the probability of selecting two red marbles in a row?
  2. What is the probability of selecting a blue marble and then a white marble?
  3. What is the probability of selecting two white marbles in a row?
  4. How does the probability change if marbles are drawn without replacement?
  5. What is the probability of selecting two marbles of the same color?

Tip: When events are independent, you can find the combined probability by multiplying the individual probabilities of each event.

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Math Problem Analysis

Mathematical Concepts

Probability
Independent Events
Multiplication Rule

Formulas

P(A and B) = P(A) × P(B) for independent events
P(Red) = 5/10 = 1/2
P(Blue) = 3/10
P(White) = 2/10 = 1/5

Theorems

Multiplication Rule for Probability of Independent Events

Suitable Grade Level

Grades 6-8