Question

Someone help me understand this problem?

Answer 1

A bag has 4 green marbles, 3 red marbles, and 3 yellow marbles. What is the probability that you pick a green marble, do not replace it, and pick a red marble?

Answer 2

Well, I believe these are two scenarios.
First calculate the probability you have to pick a green marble, you count all the marbles and and the green marbles:
\[\frac{ 4 }{ 10 }.100\]

Answer 3

why the 100?

Answer 4

it's there by mere definition, but it's a formula that gives you the probability.

Answer 5

You have to first perform the division, remember that.

Answer 6

I got 40

Answer 7

Good, now, that gives the probability you would have to get a green marble, now, you won't put it back in the bag, so now you have a total of 9 marbles inside the bag.
What would be the probability to find a red marble in the new quatity?:
\[\frac{ 3 }{ 9 }.100\]

Answer 8

got 33.33

Answer 9

Better not multiply by a 100. Only if you want to convert the final answer to a percentage
$$ \Large \sf Probability = \frac {4}{10}\cdot \frac{3}{9}$$

Answer 10

2/15??

Answer 11

yes

Answer 12

awwwh okay thank you!
i'll look at this next time i have trouble with this

Answer 13

Haha, I was doing it by parts, but thanks, perl.

Answer 14

@perl @Owlcoffee so for the problem

A bag has 5 red marbles, 6 blue marbles and 4 black marbles. What is the probability of picking a blue marble, replacing it, and then picking another blue marble?

the answer would be 4/25 ?