Answer:
The total number of samples that contain at least 3 red balls is 115.
Step-by-step explanation:
Total number of balls = 11
Total number of red balls = 6
Total number of white balls = 5
A sample of 4 balls is to be selected that contain at least 3 red. It means either 3 out of 4 balls are red or 4 out of 4 ball are red.
Combination formula:
Using this formula we get
Therefore the total number of samples that contain at least 3 red balls is 115.