Question

There is a bag filled with 4 blue, 3 red and 5 green marbles.
A marble is taken at random from the bag, the colour is noted and then it is not replaced.
Another marble is taken at random.
What is the probability of getting 2 greens?

Answer 1

Answer:

5/11

Step-by-step explanation:

Total number of marbles = 4 + 3 + 5 = 12

As a marble is taken and not replaced , the total number of marbles becomes 12 - 1 =11

Number of green balls = 5

Probability of getting green ball = 5/11

Answer 2

There is a bag filled with 4 blue, 3 red and 5 green marbles. A marble is taken at random from the bag, the colour is noted and then it is replaced. Another marble is taken at random. What is the probability of getting 2 blues?

We have (4 blue + 3 red + 5 green) = 12 total marbles

With replacement, the probability of getting one blue is 4/12 = 1/3

Since each draw is independent of the last, the probability of Blue, Blue = 1/3 * 1/3 = 1/9