Please help, and quickly!

In a class of 28 students, the teacher selects four people at random to participate in a geography contest. What is the probabil

mixer [17]

Using the hypergeometric distribution, it is found that there is a 0.0452 = 4.52% probability that this group of four students includes at least two of the top three geography students in the class.

The students are chosen without replacement, hence the <em>hypergeometric distribution</em> is used to solve this question.

<h3>What is the hypergeometric distribution formula?</h3>

The <em>formula </em>is:

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}C_{N-k,n-x}}{C_{N,n}}$

$C_{n,x} = \frac{n!}{x!(n-x)!}$

The parameters are:

x is the number of successes.

N is the size of the population.

n is the size of the sample.

k is the total number of desired outcomes.

In this problem:

There are 28 students in class, hence $N = 28$ .

Four people will be chosen at random, hence $n = 4$ .

The top three is composed by 3 people, hence $k = 3$ .

The probability that this group of four students includes at least two of the top three geography students in the class is:

$P(X \geq 2) = P(X = 2) + P(X = 3)$

In which:

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}C_{N-k,n-x}}{C_{N,n}}$

$P(X = 2) = h(2,28,4,3) = \frac{C_{3,2}C_{25,2}}{C_{28,4}} = 0.0440$

$P(X = 3) = h(3,28,4,3) = \frac{C_{3,3}C_{25,1}}{C_{28,4}} = 0.0012$

Then:

$P(X \geq 2) = P(X = 2) + P(X = 3) = 0.0440 + 0.0012 = 0.0452$

0.0452 = 4.52% probability that this group of four students includes at least two of the top three geography students in the class.

You can learn more about the hypergeometric distribution at brainly.com/question/4818951

3 0

2 years ago

50 POINTSS MORE !!!!!

Andreas93 [3]

The time it will take for the block of ice to melt if the temperature is 45 degrees is 3 hours.

The cost to travel 22 miles is 55 dollars.

let

time it takes for ice to melt = x

air temperature = y

Therefore,

x ∝ 1 / y

x = k / y

when x = 2.5 hours and y = 54 degrees

Hence,

k = 2.5 × 54

k = 135

The time it will take for the block to melt at 45 degrees = 135 / 45 = 3 hours

<h3>How to find equation that relates the cost to the number of miles?</h3>

It costs $35 for a ride from the city centre to the airport, 14 miles away.

where

c = cost

m = number of miles

Therefore, the equation is as follows:

35 / 14 = 2.5

c = 2.5m

Hence, when you travel 22 miles,

c = 22(2.5)

c = 55 dollars

learn more on equation here: brainly.com/question/22737982

#SPJ1

6 0

2 years ago

Find the value of ln(-7).

const2013 [10]

Answer:

A

Step-by-step explanation:

Here, we want to find the value of ln (-7)

ln is same as Log to base e and mathematically , we have it for positive numbers only

For that of negative numbers, we get undefined results

However, by the use of special mathematical

methods, we have the answer for ln (-7) as;

1.94591015 + 3.14159265 i

As we can see, for the second part, the value for the coefficient of the complex number is pi and thus, we have the correct option as A

4 0

2 years ago

Marty went shopping for school supplies. He bought a package of pens for $2.25, a package of paper for $3.25, a notebook for $5.

Marat540 [252]

Answer:

$3.50

Step-by-step explanation:

to find the range you take the highest number and the lowest number and subtract them

so with that, let us do just that-

$5.75, $3.75, $3.25, $2.25

$5.75-$2.25

=$3.5

and since we're dealing with money we must add a '0' to the end of the decimal- $3.50

good luck :)

i hope this helps

brainliest would be highly appreciated

have a nice day!

8 0

3 years ago

Adjust the equation so the line passes through the points. Y=x+1

lapo4ka [179]

Answer:

Slope=

2.000

=1.000

x−intercept=

−1

1

=−1.00000

y−intercept=

1

=1.00000

Step-by-step explanation:

Rearrange:

Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation :

y-(x+1)=0

STEP

1

:

Equation of a Straight Line

1.1 Solve y-x-1 = 0

Tiger recognizes that we have here an equation of a straight line. Such an equation is usually written y=mx+b ("y=mx+c" in the UK).

"y=mx+b" is the formula of a straight line drawn on Cartesian coordinate system in which "y" is the vertical axis and "x" the horizontal axis.

In this formula :

y tells us how far up the line goes

x tells us how far along

m is the Slope or Gradient i.e. how steep the line is

b is the Y-intercept i.e. where the line crosses the Y axis

The X and Y intercepts and the Slope are called the line properties. We shall now graph the line y-x-1 = 0 and calculate its properties

Graph of a Straight Line :

Calculate the Y-Intercept :

Notice that when x = 0 the value of y is 1/1 so this line "cuts" the y axis at y= 1.00000

y-intercept = 1/1 = 1.00000

Calculate the X-Intercept :

When y = 0 the value of x is 1/-1 Our line therefore "cuts" the x axis at x=-1.00000

x-intercept = 1/-1 = -1.00000

Calculate the Slope :

Slope is defined as the change in y divided by the change in x. We note that for x=0, the value of y is 1.000 and for x=2.000, the value of y is 3.000. So, for a change of 2.000 in x (The change in x is sometimes referred to as "RUN") we get a change of 3.000 - 1.000 = 2.000 in y. (The change in y is sometimes referred to as "RISE" and the Slope is m = RISE / RUN)

Slope = 2.000/2.000 = 1.000

Geometric figure: Straight Line

1. Slope = 2.000/2.000 = 1.000

2. x-intercept = 1/-1 = -1.00000

3. y-intercept = 1/1 = 1.00000

3 0

3 years ago