Answer:
a. P(x>20)=0.19
b. P(x≥6)=0.72
c. P(x≤20)=0.81
d. A and C
Step-by-step explanation:
We know that:
1) the probability that a student makes fewer than 6 mistakes is 0.28

2) The probaiblity that a student makes between 6 to 20 mistakes is 0.53.

We will express the proabilibities in function of the information we have.
a. Probability that a student makes more than 20 mistakes.

b. Probability that the student make 6 or more mistakes

c. Probability that a student makes 20 mistakes at most

d. A and C, because A takes a event of more than 20 mistakes and C takes the event of 20 or less mistakes. Both events cover a probability of 1.
I think this is the Domain. Since a domain is a group of numbers that can be entered in a function to create a valid output. They are set of all possible values of x which will satisfy a ffunction and output real y-values
The <span>expression that represents n plus 7 multiplied by 3 is
(n + 7)(3)
The entire expression, (n + 7) is multiplied by 3 since it would be inconvenient to state the expression as given above if what is meant was
(n + 7x3). It would have simply been n plus 21.</span>
The answer is 280 because if you multiply 400 by .3 you get 120 and if you subtract 120 from 400 you get 280