Question

A bag has 10 marbles and 4 are black. Joseph picks 2 marbles without replacing the first. What is the probability that both are black?

Answer 1

To find the probability that both marbles drawn by Joseph are black, you need to consider the number of ways he can draw 2 black marbles out of the 4 black marbles in the bag, divided by the total number of ways he can draw 2 marbles from the 10 marbles in the bag without replacement. The probability is 2/15.

Step-by-step explanation:

To find the probability that both marbles drawn by Joseph are black, we need to consider the number of ways he can draw 2 black marbles out of the 4 black marbles in the bag, divided by the total number of ways he can draw 2 marbles from the 10 marbles in the bag without replacement.

Let's calculate:

1. Number of ways to choose 2 black marbles out of 4: C(4,2) = 6.
2. Number of ways to choose 2 marbles out of 10 without replacement: C(10,2) = 45.

Therefore, the probability that both marbles are black is 6/45, which simplifies to 2/15.

Answer 2

If there are 10 marbles in total then the probability is 2/10