Question

Without looking, Tammy takes a marble out of a bag that contains 10 red marbles, 15 green marbles, and 25 blue marbles. She records its color and returns the marble to the bag. If Tammy repeats the proess 90 times, how many times can she expect to pull a red marble? Please explain, I don't get this. Thank you and God bless you.

Answer 1

Since there are 10 reds out of 50 marbles,
the prob(red) = 10/50 = 1/5

Since the marble is returned, each turn is independent on the results of any previous or future draw
So in 90 draws we expect (1/5)(90) or 18 reds

Answer 2

10/50 of the total draws

Answer 3

Thank you very much, I kindly appreciate you both. God bless you both.