2010020101

SubArea: 
Probability
Level: 
A
Project ID: 
2010020101
Source Problem: 
2010020102
Accepted: 
0
Clonable: 
1
Easy: 
0
An urn contains 12 red balls and 30 blue balls. Find the minimum number of red balls that must be added so that the probability of drawing a red ball is greater than 0.66.
47
27
37
17