## anonymous one year ago WILL MEDAL AND FAN (06.02)A bag contains 30 marbles, 3 of which are blue, 20 are red, 5 are green, and 2 are purple. Emerson takes a marble out of the bag, records the color, and returns it to the bag. How many purple marbles should he expect after 300 trials? 20 30 50 200

1. anonymous

@Hero @Preetha

2. anonymous

anybody?

3. anonymous

@nerlineg

4. anonymous

On any draw, what is the probability of choosing a purple marble?

5. anonymous

idk, but i think it is 20

6. anonymous

How many purple marbles are there?

7. kropot72

The probability of drawing a purple marble is 2/30 on each trial. The expected number of purple marbles after 300 trials is therefore $\large \frac{2}{30}\times\frac{300}{1}=?$

8. anonymous

i think so because all of the marbles added up = 30, and 30 x 10 = 300

9. anonymous

2 x 10 = 20

10. kropot72

Correct.

11. anonymous

and 600/30

12. anonymous

so it is 20?

13. kropot72

Yes.

14. anonymous

thank u!

15. kropot72

you're welcome :)