Question

A box contains 4 red and 5 green marbles. if 6 marbles are drawn without replacement, what is the expected number of red marbles?

Answer 1

The expected number of red marbles is 0.819.

Step-by-step explanation:

To find the expected number of red marbles, we need to consider the probabilities of drawing red marbles in each draw without replacement. In this case, there are 4 red marbles and 9 total marbles.

For the first draw, the probability of drawing a red marble is 4/9.

For the second draw, the probability of drawing a red marble changes because one red marble has already been removed from the box. There are now 3 red marbles and 8 total marbles remaining, giving a probability of 3/8.

To find the expected number of red marbles, we multiply the probability of drawing a red marble in each draw and sum the results:

E = (4/9) + (3/8) = 0.444 + 0.375 = 0.819.

Answer 2

i hope this helps i believe it is 1/3