The harmonic mean of two positive integers is the reciprocal of the arithmetic mean of their reciprocals. For how many ordered pairs $(x,y)$ of positive integers is the harmonic mean of $x$ and $y$ equal to $20$

Answers

Answer 1

Answer:

  9 ordered pairs

Step-by-step explanation:

The requirement that the harmonic mean of two positive integers be 20 places a restriction on what those integers may be.

  20 = 2/(1/x +1/y)

  y = 10x/(x -10)

Integer values of x that produce integer values of y are ...

  x ∈ {11, 12, 14, 15, 20, 30, 35, 60, 110}

The corresponding 9 ordered pairs are ...

  (11, 110), (12, 60), (14, 35), (15, 30), (20, 20), (30, 15), (35, 14), (60, 12), (110, 11)


Related Questions

Kaya rented a limousine for prom. There was one-time charge of $100, plus an hourly rate of $45. Her total cost for the night was $347.50. How many hours did Kaya rent the limo for?

Answers

Answer:

5 and a half hours

Step-by-step explanation:

347.5-100=247.5

247.5/45=5.5

Answer:

Kaya rented the limo for about 5 and a half hours

                             Hope this helps! good luck :)

4= 2f -2 i need help

Answers

Answer:

f=3

Step-by-step explanation:

4=2f-2

6=2f

f=3

Answer:

f=3

Step-by-step explanation:

trigonometry Review!
Trigonometric Ratios: Find each trig ratio. Give your answer as a fraction in simplest form.

Answers

Answer:

9. Tan(57°)=~9.24 or 231/25

10. Sin(31°)= ~9.79 or ... 979/100

11. Sin(x°)= 15/23

12. Tan(x°)=37/8

Step-by-step explanation:

9. For the side length, we must use the given angle and the given side. We want to find the opposite given the adjacent side length of 6. We multiply tan(57°) by 6 using a scientific or graphing calculator and we get the answer  9.24 (after rounding) and then convert to a fraction in simplest form since it asked for a fraction. We would get 231/25

10. Just like the last question, we are given the opposite side length but not the hypotenuse. For this, we use sin. Multiply sin(31°) by 19 and we will getb 9.79 after rounding. Convert this into a fraction and we get 979/100 as the simplest form.

11. For this question we have 2 sides but not the angle. For this, we must use the SOH CAH TOA rule and just connect the pieces. We have the opposite and the hypotenuse or OH which means we have S which is sin. We then write Sin(x°)=15/23

12. For this we have the adjacent and opposite which is OA and that leaves us with T which is Tan(x°)=37/8. Remember that opposite comes before adjacent which is why it isn't 8/37. Hope this helps! (btw I'm not a bot)

Write the equation of the line going through the points A(3, 2) and B(5, -4). Then graph.

Answers

I’m not sure what the equation is but I hope this helps

PLEASE HELP!!!!!!!!!!!!!!!!!!!!!!

Answers

Answer:

E, 3/2

Step-by-step explanation:

First, say that the numerator is 2^2001 * 3^2001 * 3^2, so that the powers will align. Then, we can combine 2^2001 and 3^2001 for 6^2001. If we ignore the 3^2, we get 6^2001/6^2002, which simplifies to 1/6. If we multiply 9 (which is 3^2) to 1/6, we get 9/6=3/2. This is a pretty tough question. Hopefully this helps!

What is Greatest value of 33,103

Answers

Answer: the greatist value is 30,000

Step-by-step explanation:

600 is invested for 3years at a 9% how much simple interest will be earned​

Answers

we have to work money every day

does anyone know the exponent rules

Answers

Does this help you at all?

The exponent rules are given below.

We are given that;

To state exponent rules

Now,

Exponent rules are the laws or principles that govern the operations on numbers or variables with exponents. An exponent is a number or a variable that tells how many times to use the base in a multiplication.

There are different exponent rules for different situations, such as multiplying, dividing, raising to another power, or having a negative or fractional exponent. Here is a table of some common exponent rules with examples:

| Rule | Example |

[tex]| x^1 = x | 6^1 = 6 |[/tex]

[tex]| x^0 = 1 | 7^0 = 1 |[/tex]

[tex]| x^-1 = 1/x | 4^-1 = 1/4 |[/tex]

[tex]| x^m * x^n = x^(m+n) | 2^3 * 2^4 = 2^(3+4) = 2^7 |[/tex]

[tex]| x^m / x^n = x^(m-n) | 2^5 / 2^3 = 2^(5-3) = 2^2 |[/tex]

[tex]| (x^m)^n = x^(mn) | (2^3)^2 = 2^(3*2) = 2^6 |[/tex]

[tex]| (xy)^n = x^n * y^n | (3*4)^2 = 3^2 * 4^2 |[/tex]

[tex]| (x/y)^n = x^n / y^n | (4/2)^3 = 4^3 / 2^3 |[/tex]

[tex]| x^(m/n) = n-th root of x^m | 2^(6/3) = cube root of 2^6 |[/tex]

We can use these rules to simplify expressions with exponents or to perform calculations with them.

Therefore, by exponentiation answer will be given.

Learn more about exponentiation here:

https://brainly.com/question/26938318

#SPJ4

The complete question is;

List all the rules of exponentiation.

Find the geometric mean of 17 and 36.

Answers

Answer:

25 is the geometric mean for two numbers

Kim is trying to lose weight. She is currently 186 lbs. Her goal is to lose 2.2 lbs. a week until she is down to 153 lbs. How many weeks will it take her to get to her goal weight?

Answers

15 weeks it will take 2.2x15 is 33-186=153

3. You have a job where you make $15 an hour. You want to
earn $165 this week so that you can buy a new stereo. How
many hours, h, do you have to work in order to earn the $165?

Answers

Answer:

11 hours

Step-by-step explanation:

HELLPPPP WHAT DOES D=

Answers

Answer:

d=8

Step-by-step explanation:

Answer:

8

Step-by-step explanation:

16*9=144

144/6=24

24/3=8

d=8

Kaitlin drove 567 miles in 9 hours. At the same rate, how long would it take her to drive 819 miles? hours

Answers

Answer:

13 hours

Step-by-step explanation:

to drive 567 miles in 9 hours you would be going 63mph and it would take 13 hours at 63 mph to travel 819 miles.

A number less than 12
Than is a switch word

Answers

Answer:

N 12

Step-by-step explanation:

If two angles are a linear pair, then they add to equal 180

Answers

True:) I helped ......

What is the approximate area of the shaded region under the standard normal curve below? Use the portion of the standard normal table to help answer the question. A normal curve with a peak at 0 is shown. The area under the curve shaded is negative 1 to positive 2. Z Probability 0. 00 0. 5000 1. 00 0. 8413 2. 00 0. 9772 3. 00 0. 9987 0. 16 0. 68 0. 81 0. 84.

Answers

The area under the curve shaded is -1 to 2 is 13.59%.

The z score is a measure used in statistic to determine by how much standard deviations the raw score is above or below the mean.

If the raw score is greater than the mean then the z score is positive but if the raw score is less than the mean then the z score is negative.

What is the formula for the z score?

The formula of z score

[tex]Z=\frac{x-\mu}{\sigma}[/tex]

[tex]\mu=mean[/tex]

[tex]\sigma=standard deviation[/tex]

x=raw score

From the normal distribution table,

Area between z = -2 and z =-1  is given by

P(-2 < z < -1) implies that  P(z < -2) - P(z < -1) that is

 P(z < -2) - P(z < -1) = 0.1587 - 0.0228

P(z < -2) - P(z < -1) = 0.1359

P(z < -2) - P(z < -1) = 13.59%

Therefore we get the area under the curve shaded is -1 to 2 is 13.59%.

To learn more about the area under the curve visit:

https://brainly.com/question/6758792

Solve the equation for z.
-2z + b = h

Answers

Answer:

z= - 1/2h + 1/2b

Step-by-step explanation:

-2z + b = h

-2z = h - b

z= - 1/2h + 1/2b

A rational function that has a domain of x # 1 and x 4 and passes through
(-3, 3). Find the function.

Answers

Step-by-step explanation:

If the domain doesn't have 1 or 4 in it. This means 1 and 4 are the zeroes of the denomiator of the rational function.

So

[tex](x - 1)(x - 4)[/tex]

[tex]( {x}^{2} - 5x + 4)[/tex]

So that is the denomiator.

The numerator passes through (-3,3).

Let A represent a posible value of the numerator.

[tex]y = \frac{a}{( {x}^{2} - 5x + 4) } [/tex]

Plug in -3 for x and 3 for y.

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

[tex]3 = \frac{a}{9 + 15 + 4} [/tex]

[tex]3 = \frac{a}{28} [/tex]

[tex]84 = a[/tex]

So one possible function is

[tex]y = \frac{84}{ {x}^{2} - 5x + 4 } [/tex]

How are parallelograms and rectangles similar and how are they different?.

Answers

A parallelogram has opposite sides equal, while in a rectangle, the opposite sides are equal with all its adjacent sides being perpendicular to each other. The diagonals of a rectangle are equal whereas the diagonals of a parallelogram are not equal.

Jake has a container in the shape of a rectangular prism. The base of the container is 30 centimeters long and 20 centimeters wide. Jake pours 0.5 gallons of water into the container. How high, in centimeters, will the water reach in the container? Note that 1 gallon is approximately equal to 3.8 liters and 1cm3 of volume can hold 1 milliliter of water.

Answers

Answer:

3.16cm

Step-by-step explanation:

Given that

1gallon=3.8liters

0.5gallon=x

x=0.5*3.8

x=1.9liters

we know that 1liter is 1000cm^3

                       1.9liter is x

x=1900cm^3

Now we have the volume of water poured in cm^3

the volume of a rectangular prism is

volume=l*w*h

1900=30*20*h

1900=600h

h=1900/600

h= 3.16cm

How many triangles can be constructed with side lengths of 6.4 cm, 8.3 cm, and 14.6 cm? 0 1 more than one

Answers

Answer:

Only one triangle is possible.

Step-by-step explanation:

Triangle inequality says that if sum of any two sides of the traingle is greater than the third side, then the triangle is possible.

Here,

,

Therefore, a triangle is possible with the given measurements,

Let us assume there is another triangle with same measurement with same measurements 7 cm, 6 cm, and 9 cm.,

By SSS congruency criteria both the triangles will be congruent.

Thus, all triangles with same measurement will be congruent to each other.

Hence, only one triangle is possible.

order the numbers from least to greatest 8.062, 8.26, 8.026, 8.6

Answers

8.026, 8.062, 8.26, 8.6

Choose the option that best completes the following statement.

If two polygons ___________, then they have the same area.

are congruent
have the same number of sides
have the same number of angles
are similar

Answers

If two polygons ARE CONGRUENT, then they have the same area.

Answer:

are congruent

Step-by-step explanation:

If two polygons are congruent, then they have the same area.

Two polygons are congruent if their corresponding sides and angles are congruent. Note: Two sides are congruent if they have the same length and angles are congruent if they have the same measure. We indicate that angles are congruent by putting the same number of slash marks through each angle.

Find the area of the parallelogram.
14 cm
E
14 cm

Answers

Answer:

area= 22cm× 14cm= 308cm²

please mark it as brainlist answer

Step-by-step explanation:

the area of trapezium is 40cm parallel sides is 12 cm and 8cm the distence between the parallel sides are

Answers

Step-by-step explanation:

Area of trapezium= 40cm²

½ h(b1+b2)=40

½ h (12+8)=40

½h (20)=40

h=40×2/20

h=4cm

And angle measure 88. 2 more than a measure of is complimentary angle what is the measure of each angle

Answers

Answer: 90 degrees

Step-by-step explanation: ez

A car takes 50.2 seconds to travel 1 mile. How long does it take the car to travel ​5.3? First round to the nearest whole number to find the estimated answer. Then find the exact answer.

Answers

266 estimated
266.06 exact

PLEASE HELP!!!


A school has 3 tons of gravel to be

spread over the playground. The

members of the landscaping crew

can move 80 pounds of gravel in each

wheelbarrow load.


How many wheelbarrow loads will it take to move all the gravel?

Answers

Using proportions, it is found that it will take 75 loads to move all the gravel.

What is a proportion?

A proportion is a fraction of a total amount, and the measures are related using a rule of three.

In one load, they mode 80 pounds. How many loads are needed to move 3 tons = 3 x 2000 = 6000 pounds? The rule of three is given as follows:

1 load - 80 pounds

x loads - 6000 pounds

Applying cross multiplication:

80x = 6000

x = 6000/80

x = 75.

It will take 75 loads to move all the gravel.

More can be learned about proportions at https://brainly.com/question/24372153

A school sells pizza slices at the concession stand during each sporting event. The school sells a mean of
200 slices per event with a standard deviation of 25 slices.
The school spends $160 of fixed costs to buy the pizza before the event and earns a revenue of $2 per
slice. They calculate their profit per event according to this formula:
profit
(total revenue) – (total costs]
What will be the mean and standard deviation of the distribution of profit per event?

Answers

Answer:

μ = $240

σ = $50

Step-by-step explanation:

Profit is revenue minus cost:

P = R – C

The revenue is $2 times the number of slices sold, and the cost is $160.

P = 2x – 160

The average profit is:

μ = 2(200) – 160

μ = 240

The standard deviation is:

σ = 2(25)

σ = 50

two numbers are respectively 20% and 50% more than the third number find the ratio of the two numbers. plz answer. will mark brainliest​

Answers

4:5
you can try it with any number for example: 10
20% more than 10 is 12
50% more than 10 is 15
12:15 or 4:5

or lets say 50
20% more than 50 is 60
50% more than 50 is 75
60:75 or 4:5
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