Answer: Did you find an answer yet?? Lol
Step-by-step explanation:
Answer:
a

b

Step-by-step explanation:
From the question we are told that
The number of students in the class is N = 20 (This is the population )
The number of student that will cheat is k = 3
The number of students that he is focused on is n = 4
Generally the probability distribution that defines this question is the Hyper geometrically distributed because four students are focused on without replacing them in the class (i.e in the generally population) and population contains exactly three student that will cheat.
Generally probability mass function is mathematically represented as

Here C stands for combination , hence we will be making use of the combination functionality in our calculators
Generally the that he finds at least one of the students cheating when he focus his attention on four randomly chosen students during the exam is mathematically represented as

Here




Hence


Generally the that he finds at least one of the students cheating when he focus his attention on six randomly chosen students during the exam is mathematically represented as

![P(X \ge 1) =1- [ \frac{^{k}C_x * ^{N-k}C_{n-x}}{^{N}C_n}]](https://tex.z-dn.net/?f=P%28X%20%20%5Cge%201%29%20%3D1-%20%5B%20%20%5Cfrac%7B%5E%7Bk%7DC_x%20%2A%20%5E%7BN-k%7DC_%7Bn-x%7D%7D%7B%5E%7BN%7DC_n%7D%5D%20)
Here n = 6
So
![P(X \ge 1) =1- [ \frac{^{3}C_0 * ^{20 -3}C_{6-0}}{^{20}C_6}]](https://tex.z-dn.net/?f=P%28X%20%20%5Cge%201%29%20%3D1-%20%5B%20%20%5Cfrac%7B%5E%7B3%7DC_0%20%2A%20%5E%7B20%20-3%7DC_%7B6-0%7D%7D%7B%5E%7B20%7DC_6%7D%5D%20)
![P(X \ge 1) =1- [ \frac{^{3}C_0 * ^{17}C_{6}}{^{20}C_6}]](https://tex.z-dn.net/?f=P%28X%20%20%5Cge%201%29%20%3D1-%20%5B%20%20%5Cfrac%7B%5E%7B3%7DC_0%20%2A%20%5E%7B17%7DC_%7B6%7D%7D%7B%5E%7B20%7DC_6%7D%5D%20)
![P(X \ge 1) =1- [ \frac{1 * 12376}{38760}]](https://tex.z-dn.net/?f=P%28X%20%20%5Cge%201%29%20%3D1-%20%5B%20%20%5Cfrac%7B1%20%20%2A%20%2012376%7D%7B38760%7D%5D%20)


Blocks would he need on the 12th step of the pattern is 34.
The correct option is A
<h3>
</h3><h3>What is series?</h3>
A series is the cumulative sum of a given sequence of terms.
Given:
We can write the series as follows:
1,4,7,10,13,.......
First term =1
common difference= 4-1=3
Using Arithmetic series
= a+11d
= 1 +11*3
= 1+33
= 34.
Hence, 34 blocks need on 12th step.
Learn more about arithmetic series here:
brainly.com/question/2171130
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