Volume of cylinder
v = πr²
v = 22/7 x 21²
v = 1385.441 cm³
Using the hypergeometric distribution, it is found that there is a 0.4286 = 42.86% probability of getting 2 of the same colour.
The marbles are chosen without replacement, hence the <em>hypergeometric </em>distribution is used to solve this question.
<h3>What is the hypergeometric distribution formula?</h3>
The formula is:


The parameters are:
- x is the number of successes.
- N is the size of the population.
- n is the size of the sample.
- k is the total number of desired outcomes.
In this problem:
- There is a total of 3 + 4 = 7 marbles, hence N = 7.
- Of those, 3 are blue, hence k = 3.
- 2 marbles will be taken, hence n = 2.
The probability of getting 2 of the same colour is the sum of P(X = 0), which is both red, with P(X = 2), which is both blue, then:



Hence:

0.4286 = 42.86% probability of getting 2 of the same colour.
You can learn more about the hypergeometric distribution at brainly.com/question/4818951
the anwser to b value is 777
Set up the problem like this: x - 4 + 8 = 44
x-4+8=44 (8-4)
x+4=44
-4 -4 (subtract 4 from both sides)
x=40
Answer: the number is 40.