Question

A bag contains 27 red marbles, 4 white marbles, and 5 gray marbles. You randomly pick out a marble, record its color, and put it back in the bag. You repeat this process 144 times. How many white or gray marbles do you expect to get

Answer 1

I would expect 16 white marbles and 20 grey balls.

Explanation:

Please see the attached

Answer 2

36

Explanation:

Firstly, let’s find the probability of taking up a white marble or a gray marble.

We add up all the marbles at first; 27 + 4 + 5 = 36 marbles

The probability of selecting a white marble is 4/36 = 1/9

The probability of selecting a gray marble is 5/36

The probability of selecting a white or gray marble is the addition of both probabilities = 4/36 + 5/36 = 9/36 or 1/4

Now out of 144 tries, how many times do we select a white or gray marble.

That would be 1/4 * 144 = 36 times

so we are expecting 36 of white or gray marbles