A bag contains 5 red,2 blue,and 4 white marbles. What is the probabiltiy If Sam picked a red marble replaced it and picked a white marble?
4/11 for the white marble
how?
11 marbles are in the bag, and 4 are white.
http://www.mathsisfun.com/data/probability.html
but the red marble is replaced
That means that the red marble is back in the bag.
no it doesnt
To find the probability, we need to determine the total number of marbles and the number of favorable outcomes.
In this case, the bag contains a total of 5 red marbles, 2 blue marbles, and 4 white marbles.
To find the probability of picking a red marble and replacing it, we consider the number of red marbles divided by the total number of marbles:
Probability of picking a red marble = Number of red marbles / Total number of marbles = 5 / (5+2+4) = 5/11.
Since Sam replaces the red marble after picking, the bag still contains 5 red marbles, 2 blue marbles, and 4 white marbles for the second pick.
To find the probability of picking a white marble as the second pick, we also consider the number of white marbles divided by the total number of marbles:
Probability of picking a white marble = Number of white marbles / Total number of marbles = 4 / (5+2+4) = 4/11.
Now, to find the probability of both events happening consecutively (picking a red marble and replacing it, then picking a white marble), we multiply the probabilities:
Probability of picking a red marble and replacing it, then picking a white marble = Probability of picking a red marble * Probability of picking a white marble = (5/11) * (4/11) = 20/121.
Therefore, the probability of Sam picking a red marble, replacing it, and then picking a white marble is 20/121.