+0  
 
0
67
1
avatar

In a bag of marbles, there are 5 brown, 6 yellow, 4 blue, 3 green, and 2 orange. What is the probability of getting 1 brown and 2 orange marbles if 3 are taken at a time?

 Mar 20, 2020
 #1
avatar+485 
+1

First, there are 5 + 6 + 4 +3 + 2 = 20 marbles total in the bag.

 

the probability of getting a brown, an orange, and another orange is equivalent to:

 

the probability of a brown * the probability of 2 oranges.

The probability of a brown marble is just (5 choose 1), or 5 ways to choose it.

Next, the number of ways to get 2 orange marbles is just (2c2), or 1.

Finally, the total number of ways to choose three marbles(our divisor) is (20 choose 3), since you're picking 3 out of 20 total 

This gives us: 

 

(5c1) * (2c2) / (20c3) =

 

5 / 1140 = 

 

1/228

 Mar 20, 2020

15 Online Users

avatar
avatar