Answer:
The probability that you get zero questions correct is 0.4096
The probability that you get one questions correct is 0.4096
The probability that you get three questions correct is 0.0256
Step-by-step explanation:
These probability can be describe with a Binomial Distribution. These distribution can be used when we have n identical and independent situations in which there is a probability p or probability of success and a probability q or probability of fail. Additionally q is equal to 1 - p. The probability of x for a situation in which we can apply binomial distribution is:

Where x is the variable that says the number of success in the n situations
And nCx is calculate as:

From the question we can identify that:
- n is equal to 4 multiple choice question
- p is 1/5 or 0.2, the probability of get one question correct
- q is 4/5 or 0.8, the probability of get one question incorrect
Then the probability of get zero questions correct of 4 questions is:

The probability of get one question correct of 4 questions is:

The probability of get three questions correct of 4 questions is:

Answer: the answer is A
Step-by-step explanation: because the original question does not state that the swimmer “randomly selected” the members. It only says the swimmer “selects” 10 members. Therefore, it is A (The sample is not random)
youre welcome
Answer:
1
Step-by-step explanation:
We have the function

and we want to know the value of
.
The first step is to find
; we can subtract 1 from it at the end! But what does
mean?
Basically, we're saying <em>"what is the value of the function when </em>
<em> ?"</em>
So, we simply replace
with 3 in the function, and we get:
.
Finally, we subtract 1 to find
.
20 mails in 1/4 day (0.25 day)
-> 1 day = 20/0.25 = 80 emails
33 photos in a 4x to 7x ratio
4x + 7x = 33
11x = 33
x = 3
33 photos can be put in a 4(3) to 7(3) ratio
which is a 12 to 21 ratio
so 12 photos on one side, and 21 on the other side to get the ratio of 4 to 7
Note:
<span>a(b) = ab = a x b = a times b</span>