Question

A bag hold 2 yellow, 1 green, and 2 red marbles. If you were to draw a marble from the bag 150 time, and replace it after it after each draw, how many yellow marbles would you expect to draw?

A. 50
B. 60
C. 30
D. 120

Answer 1

@BillBell

Answer 2

Im thinking B

Answer 3

1/5 chance of selecting yellow on any given draw. 150 selections.

150 * 1/5 = 30 would be expected.

To see this think of a much simpler situation. If you tossed a coin 150 times how many times would you see a head? How did you get that number? The same principle applies here.

Answer 4

OK, I'm wrong. You're right. As always my arithmetic is pretty bad. 2 marbles out of 5 is not 1/5. It's 2/5. 150 * 2/5 = 60.

Sorry about that.

Answer 5

its ok

Answer 6

thanks for explaining :)

Answer 7

You're welcome. I'm quite absent-minded. My wife laughs at me.