Answer:
Number of students in district = 3,055 students
Step-by-step explanation:
Given:
Ratio [Teachers to students] = 2 : 47
Total number of teachers in district = 130
Find:
Number of students in district
Computation:
Number of students in district = Total number of teachers in district[47/2]
Number of students in district = 130[47/2]
Number of students in district = 65[47]
Number of students in district = 3,055 students
Using a discrete probability distribution, it is found that:
a) There is a 0.3 = 30% probability that he will mow exactly 2 lawns on a randomly selected day.
b) There is a 0.8 = 80% probability that he will mow at least 1 lawn on a randomly selected day.
c) The expected value is of 1.3 lawns mowed on a randomly selected day.
<h3>What is the discrete probability distribution?</h3>
Researching the problem on the internet, it is found that the distribution for the number of lawns mowed on a randomly selected dayis given by:
Item a:
P(X = 2) = 0.3, hence, there is a 0.3 = 30% probability that he will mow exactly 2 lawns on a randomly selected day.
Item b:

There is a 0.8 = 80% probability that he will mow at least 1 lawn on a randomly selected day.
Item c:
The expected value of a discrete distribution is given by the <u>sum of each value multiplied by it's respective probability</u>, hence:
E(X) = 0(0.2) + 1(0.4) + 2(0.3) + 3(0.1) = 1.3.
The expected value is of 1.3 lawns mowed on a randomly selected day.
More can be learned about discrete probability distributions at brainly.com/question/24855677
A function assigns the values. The value of f(-3) and f(3) + f(-3) is 8 and -8, respectively.
<h3>What is a Function?</h3>
A function assigns the value of each element of one set to the other specific element of another set.
Given the function f(x)=-x²-4x+5, therefore, the value of f(x) when the value of x is -3 is,
f(-3) = -(-3)² - 4(-3) + 5
f(-3) = -9 + 12 + 5
f(-3) = 8
Now, the value of f(x) when the value of x is 3 is,
f(3) = -(3)²-4(3)+5
f(3) = - 9 - 12 + 5
f(3) = -16
further, the value of f(3) + f(-3) is,
f(3) + f(-3) = -16 + 8
f(3) + f(-3) = -8
Hence, the value of f(-3) and f(3) + f(-3) is 8 and -8, respectively.
Learn more about Function:
brainly.com/question/5245372
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Answer:
A. (-1 , 3)
Step-by-step explanation:
2x + y = 1
plus 3x - y = -6
------------------------------
5x = -5
x = -1
y = 1 - (2*-1) = 3