City A had a population of 10000 in the year 1990. City A’s population grows at a constant rate of 3% per year. City B has a population that is growing exponentially. In the year 2000, there were half as many people in B as in A. In the year 2010, the population of A was 20% more than the population of B.
When will the populations be equal? Give your answer in years after 1990.

Answers

Answer 1

Answer:

City A and city B will have equal population 25years after 1990

Step-by-step explanation:

Given

Let

[tex]t \to[/tex] years after 1990

[tex]A_t \to[/tex] population function of city A

[tex]B_t \to[/tex] population function of city B

City A

[tex]A_0 = 10000[/tex] ---- initial population (1990)

[tex]r_A =3\%[/tex] --- rate

City B

[tex]B_{10} = \frac{1}{2} * A_{10}[/tex] ----- t = 10 in 2000

[tex]A_{20} = B_{20} * (1 + 20\%)[/tex] ---- t = 20 in 2010

Required

When they will have the same population

Both functions follow exponential function.

So, we have:

[tex]A_t = A_0 * (1 + r_A)^t[/tex]

[tex]B_t = B_0 * (1 + r_B)^t[/tex]

Calculate the population of city A in 2000 (t = 10)

[tex]A_t = A_0 * (1 + r_A)^t[/tex]

[tex]A_{10} = 10000 * (1 + 3\%)^{10}[/tex]

[tex]A_{10} = 10000 * (1 + 0.03)^{10}[/tex]

[tex]A_{10} = 10000 * (1.03)^{10}[/tex]

[tex]A_{10} = 13439.16[/tex]

Calculate the population of city A in 2010 (t = 20)

[tex]A_t = A_0 * (1 + r_A)^t[/tex]

[tex]A_{20} = 10000 * (1 + 3\%)^{20}[/tex]

[tex]A_{20} = 10000 * (1 + 0.03)^{20}[/tex]

[tex]A_{20} = 10000 * (1.03)^{20}[/tex]

[tex]A_{20} = 18061.11[/tex]

From the question, we have:

[tex]B_{10} = \frac{1}{2} * A_{10}[/tex]  and  [tex]A_{20} = B_{20} * (1 + 20\%)[/tex]

[tex]B_{10} = \frac{1}{2} * A_{10}[/tex]

[tex]B_{10} = \frac{1}{2} * 13439.16[/tex]

[tex]B_{10} = 6719.58[/tex]

[tex]A_{20} = B_{20} * (1 + 20\%)[/tex]

[tex]18061.11 = B_{20} * (1 + 20\%)[/tex]

[tex]18061.11 = B_{20} * (1 + 0.20)[/tex]

[tex]18061.11 = B_{20} * (1.20)[/tex]

Solve for B20

[tex]B_{20} = \frac{18061.11}{1.20}[/tex]

[tex]B_{20} = 15050.93[/tex]

[tex]B_{10} = 6719.58[/tex] and [tex]B_{20} = 15050.93[/tex] can be used to determine the function of city B

[tex]B_t = B_0 * (1 + r_B)^t[/tex]

For: [tex]B_{10} = 6719.58[/tex]

We have:

[tex]B_{10} = B_0 * (1 + r_B)^{10}[/tex]

[tex]B_0 * (1 + r_B)^{10} = 6719.58[/tex]

For: [tex]B_{20} = 15050.93[/tex]

We have:

[tex]B_{20} = B_0 * (1 + r_B)^{20}[/tex]

[tex]B_0 * (1 + r_B)^{20} = 15050.93[/tex]

Divide [tex]B_0 * (1 + r_B)^{20} = 15050.93[/tex] by [tex]B_0 * (1 + r_B)^{10} = 6719.58[/tex]

[tex]\frac{B_0 * (1 + r_B)^{20}}{B_0 * (1 + r_B)^{10}} = \frac{15050.93}{6719.58}[/tex]

[tex]\frac{(1 + r_B)^{20}}{(1 + r_B)^{10}} = 2.2399[/tex]

Apply law of indices

[tex](1 + r_B)^{20-10} = 2.2399[/tex]

[tex](1 + r_B)^{10} = 2.2399[/tex] --- (1)

Take 10th root of both sides

[tex]1 + r_B = \sqrt[10]{2.2399}[/tex]

[tex]1 + r_B = 1.08[/tex]

Subtract 1 from both sides

[tex]r_B = 0.08[/tex]

To calculate [tex]B_0[/tex], we have:

[tex]B_0 * (1 + r_B)^{10} = 6719.58[/tex]

Recall that: [tex](1 + r_B)^{10} = 2.2399[/tex]

So:

[tex]B_0 * 2.2399 = 6719.58[/tex]

[tex]B_0 = \frac{6719.58}{2.2399}[/tex]

[tex]B_0 = 3000[/tex]

Hence:

[tex]B_t = B_0 * (1 + r_B)^t[/tex]

[tex]B_t = 3000 * (1 + 0.08)^t[/tex]

[tex]B_t = 3000 * (1.08)^t[/tex]

The question requires that we solve for t when:

[tex]A_t = B_t[/tex]

Where:

[tex]A_t = A_0 * (1 + r_A)^t[/tex]

[tex]A_t = 10000 * (1 + 3\%)^t[/tex]

[tex]A_t = 10000 * (1 + 0.03)^t[/tex]

[tex]A_t = 10000 * (1.03)^t[/tex]

and

[tex]B_t = 3000 * (1.08)^t[/tex]

[tex]A_t = B_t[/tex] becomes

[tex]10000 * (1.03)^t = 3000 * (1.08)^t[/tex]

Divide both sides by 10000

[tex](1.03)^t = 0.3 * (1.08)^t[/tex]

Divide both sides by [tex](1.08)^t[/tex]

[tex](\frac{1.03}{1.08})^t = 0.3[/tex]

[tex](0.9537)^t = 0.3[/tex]

Take natural logarithm of both sides

[tex]\ln(0.9537)^t = \ln(0.3)[/tex]

Rewrite as:

[tex]t\cdot\ln(0.9537) = \ln(0.3)[/tex]

Solve for t

[tex]t = \frac{\ln(0.3)}{ln(0.9537)}[/tex]

[tex]t = 25.397[/tex]

Approximate

[tex]t = 25[/tex]


Related Questions

It takes Alice 90 minutes to put a futon frame together, and it takes Maya 60 minutes to put the same
type of frame together. If they worked together, how long would it take to put a frame together?

Answers

Answer:

36 minutes

Step-by-step explanation:

The equation to determine the time together is

1/a + 1/b = 1/c  where a and b are the times alone and c is the time together

1/90  + 1/ 60 = 1/c

Multiply each side by 180c to clear the fractions

180c( 1/90  + 1/ 60 = 1/c)

2c + 3c = 180

5c = 180

Divide each side by 5

5c/5 = 180/5

c =36

What is the proof the outcome (not A)?

Answers

9514 1404 393

Answer:

  B

Step-by-step explanation:

If the probability of event "A" is 'p', then the probability of the event "not A" is

  P(not A) = 1 - P(A) = 1 - p

For p=0.5, this is ...

  P(not A) = 1 -0.5 = 0.5 . . . . . matches choice B

Answer:

B. 0.5 is the proof the outcome (not A).

If the measure of arc CB is 8/3 units, what is the measure of CAB?

Answers

Question:

If the measure of arc CB is [tex]\frac{8}{3} \pi[/tex] units, what is the measure of ∠CAB?

Answer:

120°

Step-by-step explanation:

The figure has been attached to this response.

The figure shows a circle centered at A and has a radius of 4 units.

Also, the length of the arc CB (as given in the question) is  [tex]\frac{8}{3} \pi[/tex] units.

The length L of an arc is given by;

L = [tex]\frac{\beta }{360} * 2\pi * r[/tex]         -----------------(i)

Where;

β = angle subtended by the arc at the center of the circle and measured in degrees

r = radius of the circle

From the question;

β = ∠CAB

r = 4 units

L =  [tex]\frac{8}{3} \pi[/tex]

Substitute these values into equation (i) as follows;

[tex]\frac{8}{3} \pi[/tex] = [tex]\frac{\beta }{360} * 2\pi * 4[/tex]

=>  [tex]\frac{8}{3} \pi[/tex] = [tex]\frac{\beta }{360} * 8\pi[/tex]

Cancel 8[tex]\pi[/tex] on both sides    

[tex]\frac{1}{3}[/tex] = [tex]\frac{\beta }{360}[/tex]

Cross multiply

3 x β = 360 x 1

3β = 360

Divide both sides by 3

[tex]\frac{3\beta }{3} = \frac{360}{3}[/tex]

β = 120°

Therefore, the measure of ∠CAB is 120°

explanation would really help​

Answers

Answer:

35

Step-by-step explanation:

the whole line is 49 and line DB is 30.

minus 16 from 30 so 30-16=14

then you minus line CB from EB so 49-14=35

that makes line EC 35

x[tex]x^{2}-8x+14=2x-7[/tex]

Answers

Answer:

[tex]x = 3\ or\ x = 7[/tex]

Step-by-step explanation:

Given

[tex]x^{2}-8x+14=2x-7[/tex]

Required

Solve

Equate to 0

[tex]x^{2}-8x-2x+14+7=0[/tex]

[tex]x^{2}-10x+21=0[/tex]

Expand

[tex]x^{2}-7x-3x+21=0[/tex]

Factorize

[tex]x(x-7)-3(x-7)=0[/tex]

Factor out x - 7

[tex](x-3)(x-7)=0[/tex]

Split

[tex]x - 3 = 0\ \ x - 7 = 0[/tex]

Solve

[tex]x = 3\ or\ x = 7[/tex]

g^2+2g-48=0
g=
Use a comma to separate answers as needed

Answers

Answer:

g = -8, 6

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right  

Equality Properties

Multiplication Property of Equality Division Property of Equality Addition Property of Equality Subtraction Property of Equality

Algebra I

QuadraticsFactoringMultiple Roots

Step-by-step explanation:

Step 1: Define

Identify

g² + 2g - 48 = 0

Step 2: Solve for g

Factor:                                                                                                               (g + 8)(g - 6) = 0Find roots:                                                                                                         g = -8, 6

The sum of two numbers is 45 and their difference is 7. Find the numbers. *

Answers

the sum of two numbers that is 45 and their difference is 7 it is 39 and 6 more like 39+6

PLEASE LOOK BELOW!!! (Will give Brainliest)
No links and pls explain!!!!

Answers

Answer:

20 = x

Step-by-step explanation:

All interiror angles in this triangle will equal 180

Set your formula up as 180 = x+5+7x-5+x then solve for x

180 = x+5+7x-5+x

180 = x + 7x + x +5 - 5

180 - 5 + 5 = 9x

180 = 9x

180 / 9 = x

20 = x

You can check your result by pluging in 20 for all x

180 = 20+5+7*20-5+20

180 = 180

Help please!
Fully factorise

Answers

Answer:

a.8y³-6y

taking common

2y(4y²-3)

is a required answer

b.

3x²-20x+12

doing middle term factorization

3x²-18x-2x+12

3x(x-6)-2(x-6)

(x-6)(3x-2)

is a required answer .

a. 2y(4y^2-3)

B (x-6) -2 (x-6)

Someone help me please
Square root of 121

Answers

11.

We can check using 11^2 which is in fact 121.

Which point on the x-axis lies on the line that passes through point P and is perpendicular to line MN?

Answers

Answer:

What is 1/3 of 814

Step-by-step explanation:

What is 1/3 of 814

Answer: I think C

Step-by-step explanation:

a + b = 300 pls help i cant find out the answer

Answers

Answer:

a= 250

b= 50

250 + 50 = 300

Step-by-step explanation:

There's many solutions but this was the first one I could come up with.

Answer:

my opinion is seince a+b=300 then the sqaure of 300= 17.3?

Step-by-step explanation:

What are the x- and y-intercepts for the graph of 3x + y = 15?

x-intercept = −3
y-intercept = 15


x-intercept = 3
y-intercept = 1


x-intercept = −3
y-intercept = 1


x-intercept = 5
y-intercept = 15

Answers

Answer:

x-intercept = 5

y-intercept = 15

Step-by-step explanation:

Change the equation to slope-intercept form: y = -3x + 15

You have the y-intercept in that equation already, so you know it's 15. To find the x-intercept, substitute 0 in for y and solve algebraically.

0 = -3x + 15

-15 = -3x

5=x

line segment GJ is a diameter of circle L.Angle K measures (4x+6)°
what is the value of x?
21
24
32
44​

Answers

Answer:

A. 21

Step-by-step explanation:

Recall: inscribed angle in a semicircle equals 90°

m<K is an inscribed angle in a semicircle = (4x + 6)°

Therefore,

4x + 6 = 90°

Solve for x. Subtract both sides by 6

4x + 6 - 6 = 90 - 6

4x = 84

Divide both sides by 4

4x/4 = 84/4

x = 21

A computer store buys a computer system at a cost of $450.20. The selling price was first at $710, but then the store
advertised a 30% markdown on the system. What is the current sale price? What is the percent mark up on the current sale
price?

Answers

Answer:

i believe it is 497 after the 30% mark down

Step-by-step explanation:

i subtracted 30% from 710

What is Limit of (3 x minus 3) Superscript five-halves Baseline as x approaches 4

Answers

Answer:

d 243

Step-by-step explanation:

The solution of given function is 243

What is limit of function?

A limit defined as the value which a function approaches as that function's inputs get closer and closer to some number

[tex]lim\ (3x-3)^\frac{5}{2} \\x\to 4[/tex]

[tex](3(4)-3)^\frac{5}{2}[/tex]

[tex](12-3)^\frac{5}{2}[/tex]

[tex](9)^\frac{5}{2}[/tex]

[tex](3^2)^\frac{5}{2}[/tex]

[tex]3^5[/tex]

243

Hence, the solution of given function is 243

Learn more about limit of function

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6 1/8 qt = ___ c please help

Answers

Answer:

24 1/2 cups

Step-by-step explanation:

we can change 6 1/8 into 49/4

there are 2 cups in 1 quart

now we can set up a proportion:

2÷1 = 'c'÷ 49/4

cross-multiply to get:

49/4 × 2 = c

49/2 = c

c = 24.5

what is an algebraic expression for the quotient w and 7?

Answers

Answer:

the quotient of w and 7

is it correct?

Step-by-step explanation:

which of these expressions is equivalent to to 7(x+3)​

Answers

Well you didn’t post the options but when you expand that expression it’s 7x + 21. Hope that helps!

On expanding the expression, we get - 7x + 21.

We have the following expression -

f(x) = 7(x + 3)

We have to write its equivalent expression.

Expand : f(x) =  [tex]$\pi (\sqrt{x} + 5)[/tex]

Expanding we get -

f(x) = [tex]$\pi \sqrt{x} + 5\pi[/tex]

According to the question, we have -

7(x + 3)

On expanding, we get -

7(x + 3) = 7x + 21

Hence, on expanding the expression, we get - 7x + 21.

To solve more questions on expanding expressions, visit the link below -

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Determine the number of solutions for the system 2x+3y=5 and -9y=6x-15

Answers

9514 1404 393

Answer:

  infinite number of solutions

Step-by-step explanation:

The two equations describe the same line.

Adding 9y+15 to the second equation makes it be ...

  15 = 6x +9y

Dividing that by 3 gives you ...

  5 = 2x +3y . . . . . . identical to the first equation

The lines intersect at every point, so there are an infinite number of solutions.

Steve earns extra money babysitting. He charges $37.00 for 4 hours and $64.75 for 7 hours. Let x represent the number of hours Steve babysits and y represent the amount he charges

Answers

Answer:$6.25

Step-by-step explanation:we have that

x------------------> represent the number of hours Steven babysits

y----------------- > represent the amount he charges

for x=6 hours

y=$37.50 ----------------> y/x=37.5/6=6.25

for x=8 hours

y=$50---------------------> y/x=50/8=6.25

therefore

y=6.25x

4/8 =?/2 please answer​

Answers

Answer:

? = 1

Step-by-step explanation:

4/8 = ?/2

Change the ? into a variable so it's easier to calculate:

Variable x = ?

4/8 = x/2

Cross multiply:

4 × 2 = 8 × x

8 = 8x

Divide both sides by 8 to isolate the variable:

1 = x

Check your work:

4/8 = 1/2

4 × 2 = 8 × 1

8 = 8

Correct!

1/2 Numerator and denominator are both divided by 4

For brainlest pls ……..

Answers

Answer:

4.5 cm²

Step-by-step explanation:

The given shape is a parallelogram , and the area of a parallelogram is ,

Area :-

1/2 * b * h

So , that,

=> A = 1/2 * 2.5 * 1.8

=> A = 4.5 cm²

Answer:

A = 4.5 m²

Step-by-step explanation:

The area (A) of a parallelogram is calculated as

A = bh ( b is the base and h the perpendicular height )

Here b = 2.5 and h = 1.8 , then

A = 2.5 × 1.8 = 4.5 m²

An ice cream shop finds that its weekly profit P (measured in dollars) as a function of the price x (measured in dollars) it charges per ice cream cone is given by the function k, defined by k(x) = 125x^2 +670x 125 where P= k(x).

Required:
a. Determine the maximum weekly profit and the price of an ice cream cone that produces that maximum profit
b. The cost of the ice cream cone is too low then the ice cream shop will not make a profit. Determine what the ice cream shop needs to charge in order to break even
c. The profit function for Cold & Creamy (another ice cream shop) is defined by the function g where gx)- k(x-2). Does the function g have at the same maximum value as k?

Answers

Answer:

The answer is below

Step-by-step explanation:

Given that k(x) = -125x² +670x - 125, where x is the charge per cone and P = k(x) is the weekly profit

a) The maximum profit is at P'(x) = 0. Therefore we have to find the derivative of the profit equation and equate it to 0.

P'(x) = k'(x) = 0

k'(x) = -250x + 670 = 0

-250x + 670 = 0

250x = 670

x = $2.68

P = k(2.68) = -125(2.68²) + 670(2.68) - 125 = $772.8

Hence the maximum profit is $772.8 when the price of each ice cream cone is $2.68

b) At break even, the profit is 0. Hence P= k(x) = 0

-125x² + 670x - 125 = 0

x = 5.17 or x = 0.19

Therefore to break even, the price of the ice cream cone needs to be $0.19 or $5.17

c) g(x) = k(x - 2)

g(x) = -125(x - 2)² + 670 (x -2) - 125

Maximum profit is at g'(x) = 0

g'(x) = -250(x-2) + 670

-250(x-2) + 670 = 0

-250x + 500 + 670 = 0

250x = 1170

x = 4.68

g(4.68) = -125(4.68 - 2)² + 670(4.68 -2) - 125 = $772.8

Therefore function g has the same maximum value as function k

Find the slope thanks

Answers

9. -4/15
10. -1/14
11. -3/4
12. -1/4
13. 11/17
14. -18/13
15. undefined
16. -30

Look Below. (Will give brianliest)

Answers

Answer:

what is your question friend? :)

what are the integers from 6 to 25​

Answers

[tex]\huge\boxed{Answer\hookleftarrow}[/tex]

Answer:

The integers from 6 to 25 are [tex]\large\bold{7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24}[/tex]

Step-by-step explanation:

Natural numbers are numbers that are greater than 0 (all numbers starting from positive 1). All natural numbers are integers. So, in this case integers = natural numbers (note :- only in this case)

Evaluate this expression for x=-5 and y=-5​

Answers

Answer:

[tex]x - 2y=5[/tex]

Step-by-step explanation:

Given

[tex]x = -5; y=-5[/tex]

[tex]x - 2y[/tex] --- missing from question

Required

Evaluate

We have:

[tex]x - 2y[/tex]

Substitute for x and y

[tex]x - 2y=-5 - 2*-5[/tex]

[tex]x - 2y=-5 +10[/tex]

[tex]x - 2y=5[/tex]

5(x+2)-4 = 13-7(x+1)

Answers

Answer:

0

Step-by-step explanation:

5x+10-4=13-7x-7

5x+6=6-7x

5x+0= -7x

0=-12x

Divide and u get x=0

Find the 66th term of the arithmetic sequence -28,-45,-62

Answers

Answer:

Using the formula

an = a of 1 + (n-1)(d)

an = -28 + (n-1)(-17)

simplify

an = -17n - 11

Now that we have the formula, we just plug in 66 for n

a66 = -17(66) - 11

a66 = -1133

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