Serect the correct answer.

In 7 hours, Goran reads 56 chapters of a book.<br> What is his rate in chapters per hour?

tensa zangetsu [6.8K]

Answer:

His rate in chapters per hour is 8 chapters per hour

Step-by-step explanation:

If you divide 56 by 7 you get 8 also if you want to check to be sure you can just multiply 8 and 7 or 7 and 8

5 0

2 years ago

A university found that 20% of its students withdraw without completing the introductory statistics course. Assume that 20 stude

EleoNora [17]

Answer:

a) $P(X \leq 2)= P(X=0)+P(X=1)+P(X=2)$

And we can use the probability mass function and we got:

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

And adding we got:

$P(X \leq 2)=0.0115+0.0576+0.1369 = 0.2061$

b) $P(X=4)=(20C4)(0.2)^4 (1-0.2)^{20-4}=0.2182$

c) $P(X>3) = 1-P(X \leq 3) = 1- [P(X=0)+P(X=1)+P(X=2)+P(X=3)]$

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

$P(X=3)=(20C3)(0.2)^3 (1-0.2)^{20-3}=0.2054$

And replacing we got:

$P(X>3) = 1-[0.0115+0.0576+0.1369+0.2054]= 1-0.4114= 0.5886$

d) $E(X) = 20*0.2= 4$

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Solution to the problem

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n=20, p=0.2)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

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

Part a

We want this probability:

$P(X \leq 2)= P(X=0)+P(X=1)+P(X=2)$

And we can use the probability mass function and we got:

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

And adding we got:

$P(X \leq 2)=0.0115+0.0576+0.1369 = 0.2061$

Part b

We want this probability:

$P(X=4)$

And using the probability mass function we got:

$P(X=4)=(20C4)(0.2)^4 (1-0.2)^{20-4}=0.2182$

Part c

We want this probability:

$P(X>3)$

We can use the complement rule and we got:

$P(X>3) = 1-P(X \leq 3) = 1- [P(X=0)+P(X=1)+P(X=2)+P(X=3)]$

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

$P(X=3)=(20C3)(0.2)^3 (1-0.2)^{20-3}=0.2054$

And replacing we got:

$P(X>3) = 1-[0.0115+0.0576+0.1369+0.2054]= 1-0.4114= 0.5886$

Part d

The expected value is given by:

$E(X) = np$

And replacing we got:

$E(X) = 20*0.2= 4$

3 0

2 years ago

3z + 3/4 - 2z<br> plz help me

Ronch [10]

Answer: z + 3/4

Step-by-step explanation:

8 0

2 years ago

What value of c in the equation cx+4y=12 would give the equation a slope of 8? please help me

Lorico [155]

Answer:

1cy

Step-by-step explanation:

c(8)+4y=12

8c+4y=12

12cy /12cy=12 /12cy

1cy

7 0

2 years ago

Question No. 4 The area of an equilateral triangle is half the area of a rhombus which in turn is equal to one third the area of

____ [38]

The ratio of the length of each side of the triangle to that of the hexagon is

<h3>What is equilateral triangle?</h3>

The triangle which has all the three sides equal in dimension is called the equilateral triangle.

According to the question,

Area of triangle = Area of rhombus = Area of hexagon

1/2 base x height = 1/2 diagonal1 xdiagonal2 = (3√3 / 2) side²

The triangle has equal base and height = a.

The hexagon has each side measuring b.

1/2 a² = (3√3 / 2) b²

Ratio of sides of triangle and hexagon is

a²/b² = 3√3

a/b = √ 5.19615

a/b = 2.2795

Thus, the ratio of each side of the triangle to that of the hexagon is 2.2795.

Learn more about equilateral triangle.

brainly.com/question/3461022

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4 0

1 year ago