Amanda went to the store to purchase ink pens. She found three kinds of pens. The first cost $4 each; the price of the second kind was 4 for $1; and the cost for the third kind was 2 for $1. She bought 20 pens and she bought at least one of each kind. (It is possible to buy only 1 of the pens that are "4 for $1" or "2 for $1".) The cost was $20. When she got back to her office, Amanda decided to turn this into a math problem for me. She asked: how many of each kind did I buy?

Answers

Answer 1

Answer:

Amanda buy first kind of pen = 3

Amanda buy second kind of pen = 2

Amanda buy third kind of pen = 15

Step-by-step explanation:

Given - Amanda went to the store to purchase ink pens. She found three    

            kinds of pens. The first cost $4 each; the price of the second kind

            was 4 for $1; and the cost for the third kind was 2 for $1. She bought

            20 pens and she bought at least one of each kind. (It is possible to

            buy only 1 of the pens that are "4 for $1" or "2 for $1".) The cost was

            $20.

To find - When she got back to her office, Amanda decided to turn this into

              a math problem for me. She asked: how many of each kind did I

              buy?

Proof -

Let Amanda buy first kind of pen = x

                      second kind of pen = y

                           third kind of pen = z

As given,

She bought total pen = 20

⇒x + y + z = 20          ...............(1)

Now,

As given,

cost for first kind pen = $4 for 1 pen

As she bought x pens of first kind , so

Cost of x pens of first kind = $4x

Now,

The price of the second kind was 4 for $1

⇒Cost of second kind = $[tex]\frac{1}{4}[/tex] for 1 pen

As she bought y pens of send kind , so

Cost of y pens of second kind = $[tex]\frac{1}{4}y[/tex]

Now,

The price of the third kind was 2 for $1

⇒Cost of third kind = $[tex]\frac{1}{2}[/tex] for 1 pen

As she bought z pens of send kind , so

Cost of z pens of third kind = $[tex]\frac{1}{2}z[/tex]

Now,

As given, The cost was $20

⇒4x + [tex]\frac{1}{4}y[/tex] + [tex]\frac{1}{2}z[/tex] = 20

⇒16x + y + 2z = 80             .....................(2)

∴ we get 2 equations

x + y + z = 20                   .....................(1)

16x + y + 2z = 80             .....................(2)

Now,

Subtract equation (1) from equation (2) , we get

16x + y + 2z  - ( x+ y + z )= 80 - 20

⇒16x + y + 2z - x - y - z = 60

⇒15x + z = 60

⇒z = 60 - 15x

Now,

Put the value of z in equation (1) , we get

x + y + 60 - 15 x = 20

⇒ y - 14x = 20 - 60

⇒y - 14x = -40

⇒14x - y = 40

⇒y = 14x - 40

Now,

we get

z = 60 - 15x

y = 14x - 40

As given

she bought at least one of each kind

it means x > 1, y > 1, z > 1

Now,

If x = 1, then y = 14 - 40 = -26

Not possible

If x = 2 , then y = 14(2) - 40 = -12

Not possible

If x = 3, then y = 14(3) - 40 = 2 and z = 60 - 15(3) = 15

Possible.

If x = 4,  then y = 14(4) - 40 = 16 and z = 60 - 15(4) = 0

Not Possible.

If x = 5, then y = 14(5) - 40 = 30 and z = 60 - 15(5) = -15

Not Possible.

∴ we get

x = 3, y = 2, z = 15

Amanda buy first kind of pen = x = 3

Amanda buy second kind of pen = y = 2

Amanda buy third kind of pen = z = 15


Related Questions

Question 11 (1 point)
Evaluate the function.
Given f(x) = x2 - 5x + 5, find f(3).

Answers

Answer:

f(3) =-1

Step-by-step explanation:

f(x) = x^2 - 5x + 5

Let x=3

f(3) = 3^2 -5(3) +5

      = 9 -15+5

      = -6+5

      =-1

f(3) = (3)2 - 5(3) + 5
f(3) = -4

Find the value of the discriminant of the following equation 10x² + x = 1.​

Answers

Answer:

41

Step-by-step explanation:

as discriminant  is b^2 -4ac

b= 1

a= 10

c = -1

then

1^2 - (4*10*-1) =  1 - (-40) = 1 + 40 = 41

Hhsudhsbd bdgehdhudhehsidbdjbdidbd is sibeidbdibbbdid



The weekly production cost C of manufacturing x watches is given by the formula C = 6000 + 3x, where the variable C is in dollars.
" (a) What is the cost of producing 1000 watches?

Answers

Answer:

therefore, to produce 1000 watches , it would cost 9000 dollars.

Price : 9 dollars a watch

Step-by-step explanation:

C=6000 + 3x

what is the cost of producing 1000 watches?

first do this

C= (1000)= 6000 + 3(1000)

C= (1000)= 6000 +3000

C= 9000

The carnival also offers two magic shows. The morning show is only 20 minutes and it costs $3.75. For the afternoon show, it is 35 minutes and costs $5.25. Which show would give you more for your money?

Answers

Answer:

35 min show

Step-by-step explanation:

3.75 / 20 = .1875

5.25 / 35 = .15

you pay less for the 35 min show

can i please get brainliest! :)

Use differences to find a pattern in the sequence.
7, 17, 30, 51, 85, 137, 212
Assuming that the pattern continues, the eighth term should be

Answers

Answer:

451

Step-by-step explanation:

7, 17, 30, 51, 85, 137, 212

Differences between              Difference between             Difference between

numbers in sequence             first differences                    second differences

17 - 7 = 10

30 - 17 = 13                                          3      

51 - 30 = 21                                          8                                                   5

85 - 51 = 34                                         13                                                  5

137 - 85 = 52                                       18                                                  5

212 - 137 = 75                                      23                                                 5

                          75 + 28 = 103

212 + 103 = 315                                  28                                                 5

                         103 + 33 = 136

315 + 136 = 451                                   33                                                5

Bryson has soccer practice for 2 1/4 hours 2 times a week. How much time does Bryson spend at soccer practice in 1 week?

Answers

15.75 is the answer for your question

Answer:

15.75

Step-by-step explanation:

Answer number 2 please

Answers

Answer:

Its 4

Step-by-step explanation:

Volume is base times wigth times height to 5*4*v has to be 60 so we know v is 4.

it’s 4 because 5x3 is 20 and then you need to get to 60 so 20x3 is 60 because of the 3 sides

200 percent of d is 18 what is d please help this is a question i have been needing help on for a long time

Answers

Step-by-step explanation:

what do u mean ??

200 per cent of 8???

If that's so, 200/ 8 * 100 = 2,500

Answer:

9

Step-by-step explanation:

When we calculate percentages, we multiply the numbers divided by 100. Therefore, 200% is the same as ×2.




3. The sum of two numbers is 30 and their difference is 12. Find the two numbers.

Answers

Answer:

I don't know is it 12 and 16 I'm not sure

Answer:

The two numbers are 21 and 9

Step-by-step explanation:

Let the two numbers be a and b

The sum of these numbers is 30

a+b=30

The difference between these numbers is 12

a−b=12

                             ―――――――――

I.  You can solve this by logic.

If the two numbers were exactly equal, then they would both be 15.

15+15=30

But the difference would be 0, not 12

So if you lowered b by one point, and added that to a, then the two numbers would be 16 and 14, and the difference would be 2.

So you can see that for every point you subtract from b to add to a, you increase the distance between them by 2

So, by logic, you need to subtract 6 points from b and add them to a to create a difference of 12

(15+6) minus (15−6) gives a difference of 12

.m21.....−mm∩9       =  12

Answer:

The two numbers are 21 and 9

                   ―――――――――

II.  You can solve this by math

These are simultaneous equations, so you can solve them by math.

.a+b=30

.a−b=12

――――――

2a +0=42

.a         =21 ← same answer

A computer game originally sold for $40 but is now on sale for 30% off. What is the sale price of the computer game?​

Answers

Answer:

28

Step-by-step explanation:

Answer:

28

Step-by-step explanation:

30% of 40 is 12, 40-12=28, the answer is 28.

7

Jackson is creating a rectangular board game that includes a diagonal line from two of the corners of the game. How long is the diagonal if the board game is 10 inches

long by 8 inches wide? Explain your reasoning. Round your answer to the nearest tenth of an inch.

Helppp

Answers

Answer:

diagonal = = 12.8 inches (to the nearest tenth of an inch)

Step-by-step explanation:

As shown in the diagram attached to this solution:

Let the Length of the rectangular board = a

Let the width = b

Let the diagonal = d

where:

a = 10 inches

b = 8 inches

d = ?

Triangle ABC in the diagram is a right-angled triangle, therefore, applying Pythagoras theorem:

(hypotenuse)² = (Adjacent)² + (Opposite)²

d² = 10² + 8²

d² = 100 + 64

d² = 164

∴ d = √(164)

d = 12.806 inches

d = 12.8 inches (to the nearest tenth of an inch)

N:B Rounding off to the nearest tenth of an inch is the same as rounding off to 1 decimal place.

Please help thank u i hope u help

Answers

Step by step

2b^3+5 when b =3

1: 2(3)^3+5
2: 2(27) since 3^3 = 27
3: 54 +5 = 59

Answer: 59

Hope this helps.
Leave a like and brainliest!

It costs $8 per hour to rent a bike. Niko graphs this relationship using x for number of hours and y for total cost in dollars. Write an ordered pair that is a point on the graph of the relationship

Answers

im pretty sure it would be (5, 40)!
the equation is y=8x :-)

Dot plot 1 is the top plot. Dot plot 2 is the bottom plot.
According to the dot plots, which statement is true?
Х
The range of the data in dot plot 1 is less
than the range of the data in dot plot 2.
10
The mean of the data in dot plot 1 is
greater than the mean of the data in data
plot 2.
Х
х
The median of the data in dot plot 1 is
equal to the median of the data in dot plot
2.
The mode of the data in dot plot 1 is less
than the mode of the data in dot plot 2.

Answers

Answer:

the answer is b. The mode of the data in dot plot 1 is less than the mode of the data in dot plot 2.

Step-by-step explanation:

In the dot plots 1 and 2, the statement which is true is that the mean of the data in dot plot 1 is greater than the mean of the data in data plot 2.

What is dot plot?

The dot plot is the way oif representation of the data. This data is plooted in the form of points or dots over an x-y axis. The dot polt is also known as the strip plot.

Dot plot 1 is the top plot. The value of it are as,

2,3,4,5,5,6,6,6,6,7,7,7,8,8,9,10

Dot plot 2 is the bottom plot. The value of it are as,

1,2,2,3,3,4,4,4,5,5,5,6,6,7,8,9

The options given in the problem are,

The range of the data in dot plot 1 is less than the range of the data in dot plot 2-

Range is difference between the highest and lowest value. The range of the first dot plot is,

[tex]r_1=10-2=8[/tex]

The range of the Second dot plot is,

[tex]r_2=9-1=8[/tex]

Range of dot plots are equal.

The mean of the data in dot plot 1 is greater than the mean of the data in data plot 2.

Mean of the dot plot one is 6.1875 and mean of the dot plot second is 4.625.

The median of the data in dot plot 1 is equal to the median of the data in dot plot

The median of the data in dot plot 1 is 6 and the median of the data in dot plot is 4.5. Thus they are not equal.

The mode of the data in dot plot 1 is less than the mode of the data in dot plot 2.

The mode of the data in dot plot 1 is 6 and the mode of the data in dot plot 2 is 4 and 5. Thus this is not correct option.

Hence, in the dot plots 1 and 2, the statement which is true is that the mean of the data in dot plot 1 is greater than the mean of the data in data plot 2.

Learn more about the dot plot  here;

https://brainly.com/question/15853311

Solve for f

-5f +5 < 15

Question 1 options:

f < 8


f > -2


f = 3


f < 2

I NEED HELP ASAP

Answers

Step-by-step explanation:

step 1. -5f + 5 < 15

step 2. -5f < 10 (subtract 5 from each side)

step 3. f > -2 (divide both sides by -5 - dont forget to flip arrow when dividing by a negative number).

find the slope of the line

Answers

Answer:

-1

Step-by-step explanation:

it goes down 1 per gain of 1 on the x axis

Answer:

-1

rise over run -2/2

slope is -1

Step-by-step explanation:

find the inequality represented by the graph pleasseee help me​

Answers

Answer:

y≥1/2x is the answer for this problem

A​ salesperson's commission rate is 5 ​%. What is the commission from the sale of 32,000 worth of​ furnaces? Use pencil and paper. Suppose sales would double. What would be true about the​ commission? Explain without using any calculations. The commission is ​$ .

Answers

Answer: Answer:

Its sad that you have to uses this app to get the right answers.

Have you ever stopped to ponder if someone is trying to scam/Catfish you?

Also I bet that you haven't even tried reading this question.

I know that you can do it yourself!

If not then, Sorry to hear.

Also

The answer is:

Do it yourself, Because if you try..You'll have a better answer then I ever could. Or anyone TBH

Simplify completely''''​

Answers

Answer:

[tex]\displaystyle \frac{2x + 5}{x - 9}[/tex]

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

BracketsParenthesisExponentsMultiplicationDivisionAdditionSubtractionLeft to Right

Algebra I

Terms/CoefficientsFactoring

Step-by-step explanation:

Step 1: Define

[tex]\displaystyle \frac{2x^2 + 13x + 20}{x^2 - 5x - 36}[/tex]

Step 2: Simplify

[Fraction] Factor numerator:                                                                         [tex]\displaystyle \frac{(x + 4)(2x + 5)}{x^2 - 5x - 36}[/tex][Fraction] Factor denominator:                                                                      [tex]\displaystyle \frac{(x + 4)(2x + 5)}{(x - 9)(x + 4)}[/tex][Fraction] Divide:                                                                                           [tex]\displaystyle \frac{2x + 5}{x - 9}[/tex]

The median number of part-time employees at fast-food restaurants in a particular city was known to be 18 last year. City officials think the use of part-time employees may be increasing. A sample of nine fast-food restaurants showed that seven restaurants were employing more than 18 part-time employees, one restaurant was employing exactly 18 part-time employees, and one restaurant was employing fewer than 18 part-time employees. Can it be concluded that the median number of part-time employees has increased

Answers

Answer:

It can be concluded that the median number of part-time employees has increased hence we will reject the null hypothesis ( H0 : p = 0.5 )

Step-by-step explanation:

Test using  α = 0.5 to determine whether the median number of part-time employees has increased

number of restaurants with more than 18 part-time employees = 7  ( + sign )

number of restaurants with less than 18 part-time employees = 1 ( - sign )

number of restaurants with exactly 18 part-time employees = 1

first step : ( state the null and alternate hypothesis )

Null hypothesis : ( H0) : median ≤ 18

Alternate hypothesis : ( Ha ) : median ≥ 18

The size of the sample ( n ) can be considered to be 8 because

number of restaurants with more than 18 part-time employees = 7  ( + sign )

number of restaurants with less than 18 part-time employees = 1 ( - sign )

Hence the actual hypothesis that should be tested will be :

H0 : p = 0.5

Ha : p ≠ 0.5

Next apply the binomial distribution to determine the number of + signs

= nP = 8 ( 0.5 ) = 4 + signs ( right tailed test i.e. upper tail of the binomial distribution )

determine the P ( ≥ 7 ) + signs in order to obtain the p-value of this right tailed test ( using the binomial probability table )

P ( ≥ 7 )+ signs  = p(7) +signs  + p(8)+signs

                         = 0.0313 + 0.0039 = 0.0352

Hence the P-value = 0.0352  is < 0.05  hence we will reject the Null hypothesis ( H0 : p = 0.5 )

hence It can be concluded that the median number of part-time employees has increased

The true statement is that, the median number of part-time employees has increased

The given parameters are:

[tex]\mathbf{n_1 = +7}[/tex] ---- restaurants with more than 18 part-time employees[tex]\mathbf{n_2 = -1}[/tex] ---- restaurants with less than 18 part-time employees [tex]\mathbf{n_3 = 1}[/tex] ---- restaurants with exactly 18 part-time employees

Using a 0.5 test of significance, the null and the alternate hypotheses are:

Null hypothesis : [tex]\mathbf{H_0 : p= 0.5}[/tex]Alternate hypothesis : [tex]\mathbf{H_a : p \ne 0.5}[/tex]

The sample size (n) is calculated using

[tex]\mathbf{n =n_1 -n_3}[/tex]

So, we have:

[tex]\mathbf{n =7 --1}[/tex]

[tex]\mathbf{n =8}[/tex]

The mean of the distribution is:

[tex]\mathbf{\bar x = np}[/tex]

This gives

[tex]\mathbf{\bar x = 8 \times 0.5}[/tex]

[tex]\mathbf{\bar x = 4}[/tex]

Using the right tailed test, we calculate the probability that a restaurant has more than 7 part-time employees.

This is calculated as:

[tex]\mathbf{P(x \ge 7+) = P(x = 7+) + P(x = 8+)}[/tex]

Using the binomial probability table, we have:

[tex]\mathbf{P(x \ge 7+) = 0.0313 + 0.0039 }[/tex]

[tex]\mathbf{P(x \ge 7+) = 0.0352}[/tex]

By comparison,

When the p-value is less than the level of significance, then we will reject the Null hypothesis

Hence, it can be concluded that the median number of part-time employees has increased

Read more about probabilities at:

https://brainly.com/question/6476990

what is the speed, if distance is 900 miles and time 300 minutes​

Answers

Answer:

3 mi/min

Step-by-step explanation:

speed =distance/time

900/300=3

How many tens are in the number 639

Answers

Answer:

63 tens are in 639 are in that number

Answer:

There are 63 full tens in 639.

Step-by-step explanation:

639÷10=63.9

Hope this helps! :)

If 3(c+d) = 5 and c = 1, what is the value of c + d?

Answers

Answer:

c+d = 5/3

Step-by-step explanation:

3(c+d) = 5

Divide each side by 3

3/3(c+d) = 5/3

c+d = 5/3

Answer:

3(1+d)=5

3×1=3

3×d=3d

:3+3d-5

3d-2

3d=2 (Devide both sides by 3)

d=2/3

Question 2 of 10
If A PQR = ASTU, which statement must be true?

Answers

Answer:

PQ = ST

Step-by-step explanation:

..................

Answer:

pq = st

Step-by-step explanation:

PLSS HELP ME TYSMMMMM

Answers

Answer:

Picture or question???????

Rob is making a pizza the radius of the pizza is 21 inches what is the circumference of the pizza using 3.14 rounded to the nearest tenth

Answers

Answer:

131.9

Step-by-step explanation:

C = 2πr

using 3.14 for π, we get C = 2(3.14)(21)

C = 2(65.94)

C = 131.88 or about 131.9

find the circumference of the circle shown below. Remember to use 3.14 for LaTeX: \piπ, and be sure to round your final answer to the nearest hundredth, as needed.

Answers

Answer:

62.8   If rounded to the nearest hundredth it is 62.80

Step-by-step explanation:

1.  Formula for circumference of a cirlcle is 2 (pi) r  where for this problem,

2 =2,

pi= 3.14 and

r= 10 (1/2 of the diameter =radius)

2.   2 x 3.14 x 10

multiply all 3 numbers above, you get 62.8

3. Depending on your teacher or the test,

62.8 is your answer, if it HAS to be to the nearest hunderedth, and it's on a specific program, it might want you to enter the "0" at the end   62.80

R+2 1/4 = 4 1/2 what does r = ?

Answers

Answer:

exact form: r= 9/4

decimal form: r=2.25

mixed number form: r= 2 1/4

Step-by-step explanation:

Answer:

R=2 1/4 or 9/4

Step-by-step explanation:

You make the 4 1/2  a 4/24 so it equals 2 1/4

Than you subtract 4 2/4-2 1/4 to get 2 1/4

Hope this helps!!

calcular

a. [1/3+4] =


b. [8-15+4]=

c. 4-√81/ √36=




Answers

Answer:

a. 1/7

b. -3

c. -50

Thor made 45 gallons of of punch. The recipe he followed called for 7/9 of the punch to be orange juice. How many gallons of orange juice did Thor use to make the punch

Answers

Answer:  35 gallons

============================================================

Work Shown:

x = orange juice amount

x = (7/9)*(total amount of juice)

x = (7/9)*45

x = (7/9)*(45/1)

x = (7*45)/(9*1)

x = 315/9

x = 35 gallons of orange juice

-------------------------

Another way to approach the problem:

Draw a rectangle and split it into 9 equal slips. If the whole rectangle's area is 45 square units, then each little skinny rectangle is 45/9 = 5 square units.

Shade in exactly 7 of these little rectangular slips. The shaded portion represents 7*5 = 35 square units, which corresponds to the answer of 35 gallons.

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