a jar contains green,red,and blue marbles.The probability of choosing a blue marble is 1/3, the probability of choosing a red marble is 1/2,the probability of choosing a green marble is 1/6.If there are 12 marbles in the jar,and then three green marbles are added,what is the new probability of choosing a red marble from the jar?
Three green marbles have been added. There are still 6 red marbles out of a total of 15. Do the numbers.
6/15 = ?
To find the new probability of choosing a red marble from the jar, we need to calculate the new total number of marbles and the new number of red marbles.
Given:
Original total number of marbles = 12
Original probability of choosing a red marble = 1/2
After adding three green marbles, the total number of marbles in the jar is:
New total number of marbles = 12 + 3 = 15
Since we only added green marbles, the number of red marbles remains the same:
New number of red marbles = original number of red marbles = 12
To find the new probability of choosing a red marble, we divide the number of red marbles by the total number of marbles:
New probability of choosing a red marble = New number of red marbles / New total number of marbles
Substituting in the values we found:
New probability of choosing a red marble = 12/15
Simplifying, we get:
New probability of choosing a red marble = 4/5
To find the new probability of choosing a red marble from the jar, we need to calculate the total number of marbles and the number of red marbles in the jar after adding three green marbles.
Initially, we have a jar with 12 marbles and the probabilities are as follows:
- Probability of choosing a blue marble: 1/3
- Probability of choosing a red marble: 1/2
- Probability of choosing a green marble: 1/6
Let's calculate the number of marbles for each color initially:
- Number of blue marbles = (1/3) * 12 = 4
- Number of red marbles = (1/2) * 12 = 6
- Number of green marbles = (1/6) * 12 = 2
Now, we add three green marbles to the jar, which makes the total number of marbles equal to 12 + 3 = 15.
Therefore, the new number of green marbles = 2 + 3 = 5.
To find the new probability of choosing a red marble, we calculate the new probability as the ratio of the number of red marbles to the total number of marbles.
New probability of choosing a red marble = Number of red marbles / Total number of marbles
New probability of choosing a red marble = 6 / 15
New probability of choosing a red marble = 2 / 5
New probability of choosing a red marble = 0.4
Thus, the new probability of choosing a red marble from the jar is 0.4 or 40%.