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3 years ago

Help with number 15 please ?!

Mathematics

2 answers:

VMariaS [17]3 years ago

7 0

Answer:

18.8

Step-by-step explanation:

Alborosie3 years ago

3 0

Answer:

Step-by-step explanation:

15)We would apply the formula for exponential growth which is expressed as

y = b(1 + r)^t

Where

y represents the population of students after t years.

t represents the number of years.

b represents the initial population of students.

r represents growth rate.

From the information given,

b = 9

r = 15% = 15/100 = 0.15

Therefore, the exponential growth function is

y = 9(1 + 0.15)^t

y = 9(1.15)^t

In 2008, t = 2008 - 2001 = 7 years

y = 9(1.15)^7

y = 24 students

16) the formula for exponential decay is expressed as

y = b(1 - r)^t

b = 24500

r = 4% = 4/100 = 0.04

Therefore, the exponential decay function is

y = 24500(1 - 0.04)^t

y = 24500(0.96)^t

In 2020, t = 2020 - 1970 = 50 years

y = 24500(0.96)^50

y = 3182 people

You might be interested in

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

3 years ago

Is 3/4 greater than 7/8?

yKpoI14uk [10]

3/4 = (2*3) / (2* 4) = 6/8

7/8.

Is 3/4 greater than 7/8?
Is like asking is 6/8 greater than 7/8? Because 3/4 is equivalent to 6/8.

The answer is No.

3 0

3 years ago

Read 2 more answers

The radius of a CD is 6cm which equation could be used to find the circumference of the CD in cm ?

9966 [12]

Answer:

2πr

Step-by-step explanation:

to find the circumference you must multiply the radius by pi and 2

5 0

2 years ago

Read 2 more answers

The length of each side of a square was decreased by 2 inches so the perimeter is now 49 inches. What was the original length of

aleksley [76]

The Original length of each side of square was 14.25 inches.

Step-by-step explanation:

Perimeter of a square is given by:

Perimeter = 4 * side

Let x be the original length of each side of square

decreasing 2 inch will mean

$x-2$

Perimeter of square after reducing 2 inches from each side

$4(x-2) = 49\\4x-8 = 49\\4x = 49+8\\4x = 57\\\frac{4x}{4} = \frac{57}{4}\\x = 14.25$

So,

The Original length of each side of square was 14.25 inches.

Keywords: Perimeter, square

Learn more about perimeter at:

#LearnwithBrainly

5 0

3 years ago

I'm too lazy to do the work by myself anyway, someone please help me thank you <3 !!

In-s [12.5K]

Answer:

Step-by-step explanation:

10-3=7

7x7=49

49 x2 = 98

Have a good day! uwu

7 0

2 years ago