Khan/khan-exercises — Issue #12754: Probability 1 - Probability 1, colored balls questions incorrect
Author: KhanBugz
Created: 2012-02-01 03:59:43+00:00
State: open
Labels: chrome, win7, wrong-or-unclear

Reporter: mkaack@hotmail.com

I've received two questions like this:
A jar contains 10 red balls, 4 green balls, and 9 blue balls.

If a ball is randomly chosen, what is the probability that it is red? Write your answer as a simplified fraction.

The solution shows 13/23, the opposite of the question.

[probability_1.html?seed=171&problem=0](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/probability_1.html?seed=171&problem=0&debug)

[Answer timeline](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/probability_1.html?seed=171&problem=0&debug&activity=%5B%5B%22incorrect-activity%22%2C%22%5C%2210%2F13%5C%22%22%2C25%5D%2C%5B%22hint-activity%22%2C%220%22%2C97%5D%2C%5B%22hint-activity%22%2C%220%22%2C98%5D%2C%5B%22hint-activity%22%2C%220%22%2C98%5D%5D)

["10/13"]

Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.77 Safari/535.7

MathJax is loaded, ready, queue length: 0