An urn contains 11 numbered balls, of which 6 are red and 5 are white. a sample of 4 balls is to be selected. how many samples contain at least 3 red balls?

Using the combination formula, it is found that 115 samples contain at least 3 red balls.

The balls are chosen without replacement, which is why the combination formula is used.

Combination formula:

is the number of different combinations of x objects from a set of n elements, given by:

In this problem, the outcomes with at least 3 red balls are:

Hence:

115 samples contain at least 3 red balls.

A similar problem is given at link

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.

c

step-by-step explanation:

-3.5 degrees per hour

step-by-step explanation:

find the unit rate:

-12   1/4 degrees           12.25 degrees

= - = -3.5 degrees per hour

      3   1/2 hours               3.5 hours