28. 5/7(x)=20
X=28
Hope this helps! :)
I am pretty sure a is the correct answer
The student should deposit atleast 3,500 to get the job done. But she can deposit a lower amount.
Answer:
There is a 44.16% probability that exactly 1 of the tested bottles is contaminated.
Step-by-step explanation:
is the number of different combinatios of x objects from a set of n elements, given by the following formula.
![C_{n,x} = \frac{n!}{x!(n-x)!}](https://tex.z-dn.net/?f=C_%7Bn%2Cx%7D%20%3D%20%5Cfrac%7Bn%21%7D%7Bx%21%28n-x%29%21%7D)
In this problem, we have that:
Total number of combinations:
![C_{22,3} = \frac{22!}{3!(18)!} = 1540](https://tex.z-dn.net/?f=C_%7B22%2C3%7D%20%3D%20%5Cfrac%7B22%21%7D%7B3%21%2818%29%21%7D%20%3D%201540)
Desired combinations:
It is 1 one 5(contamined) and 2 of 17(non contamined). So:
![C_{5,1}*C_{17,2} = 5*17*8 = 680](https://tex.z-dn.net/?f=C_%7B5%2C1%7D%2AC_%7B17%2C2%7D%20%3D%205%2A17%2A8%20%3D%20680)
What is the probability that exactly 1 of the tested bottles is contaminated?
![P = \frac{680}{1540} = 0.4416](https://tex.z-dn.net/?f=P%20%3D%20%5Cfrac%7B680%7D%7B1540%7D%20%3D%200.4416)
There is a 44.16% probability that exactly 1 of the tested bottles is contaminated.