Math Problem Statement

A bag contains 11 red marbles and 4 green marbles. what are the odds of a red marble first then a red marble second without replacing

Solution

To find the probability of drawing two red marbles in succession without replacement from a bag containing 11 red marbles and 4 green marbles (15 marbles total), we proceed step by step:

Step 1: Probability of drawing a red marble first

  • There are 11 red marbles out of 15 total marbles.
  • So, the probability of drawing a red marble first is: P(Red 1st)=1115P(\text{Red 1st}) = \frac{11}{15}

Step 2: Probability of drawing a red marble second without replacement

  • After drawing one red marble, there are now 10 red marbles left, and only 14 total marbles remain.
  • So, the probability of drawing a second red marble is: P(Red 2nd | Red 1st)=1014P(\text{Red 2nd | Red 1st}) = \frac{10}{14}

Step 3: Multiply the probabilities

The overall probability of drawing two red marbles in a row without replacement is: P(Red 1st and Red 2nd)=1115×1014P(\text{Red 1st and Red 2nd}) = \frac{11}{15} \times \frac{10}{14} P(Red 1st and Red 2nd)=110210=1121P(\text{Red 1st and Red 2nd}) = \frac{110}{210} = \frac{11}{21}

Thus, the probability of drawing two red marbles in succession without replacement is 1121\frac{11}{21}.

Would you like further details or any additional questions?

Here are 5 related questions for further practice:

  1. What is the probability of drawing two green marbles in a row without replacement?
  2. What are the odds of drawing a red marble first and a green marble second without replacement?
  3. If one marble is drawn and replaced, what are the odds of drawing two red marbles in a row?
  4. How does the probability change if there are 6 green and 9 red marbles?
  5. What is the probability of drawing one red and one green marble in any order without replacement?

Tip: When calculating probabilities without replacement, remember that the total number of items decreases after each draw.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Probability
Combinatorics
Dependent Events

Formulas

P(A and B) = P(A) * P(B | A)
P(\text{Red 1st}) = \frac{11}{15}
P(\text{Red 2nd | Red 1st}) = \frac{10}{14}

Theorems

Multiplication Rule for Dependent Events

Suitable Grade Level

Grades 6-8