Two teachers, Mr. Donahue and Mrs. Ortiz, decide to buy mechanical pencilsand rulers for their classrooms. Mrs. Ortizbuys 50 mechanical pencils and 30 rulers for $55. Mr. Donahue buys 30 of each for $45. What was the price per mechanical pencil?What was the price per ruler?a.

Answers

Answer 1

Answer:

Price per mechanical pencil: [tex]\$ 0.5[/tex].

Price per ruler: [tex]\$ 1[/tex].

Step-by-step explanation:

Let the cost per mechanical pencil be [tex]\$ p[/tex], and let the cost per ruler be [tex]\$ r[/tex].

Set up two equations based on the amount of money that each teacher paid.

The cost of [tex]50[/tex] mechanical pencils ([tex]\$ p[/tex] each) and [tex]30[/tex] rulers ([tex]\$ r[/tex] each) would be [tex](50 \, p + 30\, r)[/tex]. That should be equal to the amount of money that Mrs. Ortiz paid. In other words, [tex]50 \, p + 30\, r = 55[/tex].

Similarly, the cost of [tex]30[/tex] mechanical pencils ([tex]\$ p[/tex] each) and [tex]30 \![/tex] rulers ([tex]\$ r[/tex] each) would be [tex](50 \, p + 30\, r)[/tex]. That should be equal to the amount of money that Mr. Donahue paid. In other words, [tex]30 \, p + 30\, r = 45[/tex].

That gives a system of two equations:

[tex]\left\lbrace \begin{aligned}& 50 \, p + 30\, r = 55 \\ & 30 \, p + 30\, r = 45 \end{aligned}\right.[/tex].

Subtract the second equation for the first:

[tex]20\, p = 10[/tex].

[tex]\displaystyle p = \frac{1}{2} = 0.5[/tex].

In other words, the cost of one mechanical pencil would be [tex]\$0.5[/tex].

Substitute [tex]p = 0.5[/tex] back to either equation and solve for [tex]r[/tex], the cost of one ruler.

[tex]50 \times 0.5 + 30\, r = 55[/tex].

[tex]30\, r = 55 - 25 = 30[/tex].

[tex]r = 1[/tex].

In other words, the cost of one ruler would be [tex]\$ 1[/tex].


Related Questions

The slope through (3, 5) and (1. y) is 3. Find y.



Really need this answer!

Answers

Step-by-step explanation:

y2 - y1 / x2 - x1  

2 = 5 - y / (3 - 1)

4 = 5 - y

y = 1

So the line with slope 2 passes through the points (1,1) and (3,5).

Hope this helps!

g(x)=w^2+7w-7 and f(x)=4w-8 and (f+g)(5)=

Answers

The value of (f + g)(5) is 65

Function

Function relates input to output . Therefore,

g(x) = w² + 7w - 7

f(x) = 4w - 8

Therefore,

(f + g) = w² + 7w - 7 + (4w - 8)

(f + g) = w² + 7w - 7 + 4w - 8

(f + g) = w² + 11w - 15

Finally,

(f + g)(5) = 5² + 11(5) - 15

(f + g)(5) = 25 + 55 - 15

(f + g)(5) = 80 - 15

(f + g)(5) = 65

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The product of 8 and x is great than 50.

Answers

Answer:

The product of 8 and 7 is greater than 50

Answer:

8x > 50

Step-by-step explanation:

A student is saving money to buy a video game. The student currently has $20 and plans to save $10 every month. Write a function that represents the
amount y (in dollars) of money that the student saves after x months

Answers

Answer:

y = amount saved in dollars

x = months

Since the student already has $20 dollars saved (20) and plans to save $10 per month (10x), the equation so far is y = 20 + 10x.

You can use this to solve questions based of the equation/situation by filling in any numbers you are given where the variables are.

Hope this helps! :)

Step-by-step explanation:

y = amount saved in dollars

x = months

y = 20 + 10x

Ans: y = 20 + 10x

In a test for ESP (extrasensory perception), a subject is told that cards the experimenter can see but the subject cannot contain a star, a circle, a wave, a triangle or a square. As the experimenter looks at each card in turn, the subject names the shape on the card. A subject who is just guessing has a one in four chance of guessing correctly on each card.
A. The count of correct guesses in 20 cards has a binomial distribution. What are n and p?
B. What is the mean number of correct guesses in 20 cards for subjects who are just guessing?
C. What is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?

Answers

Answer:

a) [tex]n = 20[/tex] and [tex]p = 0.25[/tex]

b) The mean number of correct guesses in 20 cards for subjects who are just guessing is 5.

c) 0.2023 = 20.23% probability of exactly 5 correct guesses in 20 cards if a subject is just guessing

Step-by-step explanation:

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

And p is the probability of X happening.

The expected value of the binomial distribution is:

[tex]E(X) = np[/tex]

The standard deviation of the binomial distribution is:

[tex]\sqrt{V(X)} = \sqrt{np(1-p)}[/tex]

A. The count of correct guesses in 20 cards has a binomial distribution. What are n and p?

20 cards mean that [tex]n = 20[/tex]

A subject who is just guessing has a one in four chance of guessing correctly on each card, which means that [tex]p = \frac{1}{4} = 0.25[/tex]

B. What is the mean number of correct guesses in 20 cards for subjects who are just guessing?

Expected value, so

[tex]E(X) = np = 20*0.25 = 5[/tex]

The mean number of correct guesses in 20 cards for subjects who are just guessing is 5.

C. What is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?

This is P(X = 5). So

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 5) = C_{20,5}.(0.25)^{5}.(0.75)^{15} = 0.2023[/tex]

0.2023 = 20.23% probability of exactly 5 correct guesses in 20 cards if a subject is just guessing

An expression is given in the box.
90 + (3d)
What is the value of the expression if c = 4 and d = 6?
O2
04
36
O 72

Answers

Answer:

the question is 9c/3d where c=4 and d=6

9*4/3*6=2

15. If R is the midpoint of OS, OR = 8x - 51 and RS = 3x - 6, find QS.
15.


PLEASE HELP

Answers

Answer:

if you mean find OS, then:

OS = 42

Step-by-step explanation:

if you mean find OS, then:

8x-51 = 3x-6

5x = 45

x = 9

OS = 2(3x-6)

OS = 6x-12

substitute for x

OS = 6(9)-12 =42

Step-by-step explanation:

ok si esoes la respuesta corecta yo les digo niños por que yo soy una profesora de mate y se mas de mate que ustedes

A fitness club charges its members a one-time fee of $40 and a monthly rate of $25. Let m represent the number of months. Write an expression for the total amount paid after m months. Then find how much a customer will have paid after 5 months. 6.EE 2, 6.EE 2a, 6.EE.6 Expression: Cost:​

Answers

Answer:

40 + 25m

40 + 25(5) = $165 after 5 months

Step-by-step explanation:

40 + 25m

40 + 25(5) = $165

11a + 22 + 17a - 6 S I M P L I F I E D

Answers

Answer:

28a +16

Step-by-step explanation:

11a + 22 + 17a - 6

28a +16

Answer:

28a + 16

Step-by-step explanation:

Combine like terms. Like terms are terms with the same variables, as well as same amount of that variable.

In this case:

11a + 17a + 22 - 6

(11a + 17a) + (22 - 6)

28a + 16

28a + 16 is your answer.

~

88% of the light aircraft that disappear while in flight in a certain country are subsequently discovered. Of the aircraft that are discovered, 72% have an emergency locator, whereas 86% of the aircraft not discovered do not have such a locator. Suppose a light aircraft has disappeared.
A) If it has an emergency locator, what is the probability that it will not be discovered?B) If it does not have an emergency locator, what is the probability that it will be discovered?C) If we consider 10 light aircraft that disappeared in flight with an emergency recorder, what isthe probability that 7 of them are discovered?

Answers

Answer:

a) [tex]P(D'/L)=0.03[/tex]

b) [tex]P(D/L')=0.7[/tex]

Step-by-step explanation:

From the question we are told that

Probability of discovered [tex]P(D)=0.88[/tex]

Probability of aircraft with locator [tex]P(L/D)=0.72[/tex]

Probability of lost aircraft without locator [tex]P(L'/D')=0.86[/tex]

Generally the probability that aircraft are not discovered is mathematically given as

[tex]P(D')=1-0.88[/tex]

[tex]P(D')=0.12[/tex]

Generally the probability that aircraft with locator are discovered is mathematically given as

[tex]P(L'/D)=1-0.72[/tex]

[tex]P(L'/D)=0.28[/tex]

Generally the  Probability of lost aircraft without locator mathematically given as

[tex]P(L/D')=1-0.86[/tex]

[tex]P(L/D')=0.14[/tex]

Generally the  Probability of having a locator mathematically given as

[tex]P(L)=P(L/D)*P(D)+P(L/D')*P(D')[/tex]

[tex]P(L)=0.72*0.88+0.14 *0.12[/tex]

[tex]P(L)=0.6504[/tex]

a)Generally the  Probability of getting lost even with locator mathematically given as

[tex]P(D'/L)=\frac{P(L/D')(P(D')}{P(L)}[/tex]

[tex]P(D'/L)=\frac{0.14*0.12}{0.6504}[/tex]

[tex]P(D'/L)=0.0258302583[/tex]

[tex]P(D'/L)=0.03[/tex]

b)Generally the  Probability of getting lost even with locator mathematically given as

[tex]P(D/L')=\frac{P(L'/D)(P(D)}{P(L')}[/tex]

[tex]P(D/L')=\frac{0.28*0.88}{1-0.6504}[/tex]

[tex]P(D/L')=0.704805492[/tex]

[tex]P(D/L')=0.7[/tex]

What value does the 7 represents in the number 94.087?

Answers

0.007, also known as the thousandths place in decimals.

It represents the thousandths place

What is the fraction equivalent of 2.151515?

Answers

Answer:

430303/200000

Step-by-step explanation:

hope this helps!!!

the question says "Find the value of the triangle shown below"

Answers

Answer:

a

Step-by-step explanation:

Answer:

[tex]\sqrt{32}[/tex]

Step-by-step explanation:

[tex]a^{2} +c^{2}=b^{2}[/tex]

which becomes 81=49+b giving you the number 32 which doesn't have a perfect square meaning the answer would be b=[tex]\sqrt{32}[/tex]

Pls answer whoever answer right first will g Brainlyiest

Answers

Answer:

D the last one

Step-by-step explanation:

Help please! This is due tomorrow!

Answers

500 centimeters is the actually height of the tree if the scale is 1-100

What is the measure of A

Answers

Answer: it is about 80%

Step-by-step explanation:

Answer:

i think about 140 degrees

Step-by-step explanation:

0.345 times 83.8 I forgot how to do it .w.

Answers

Answer:

28.911

Step-by-step explanation:

you just have to open up a calculator lol

Match the labeled points on the graph to statements about their coordinates Two numbers with a sum of 2

Answers

Answer:

see explanation!

Step-by-step explanation:

Line N

A set of points where the coordinates of each point have a sum of 2

Line M

A set of points where the y-coordinates of each point is 10 less than its x-coordinate

Any coordinate on N has a sum of 2.

Any coordinate on M has a y that is 10 less than the x.

The matching of the given labeled points provided on the graph regarding their statements would be as follows:

Line n - A set of points where the coordinates of each point have a sum of 2 Line m - A set of points where the y-coordinate of each point is 10 less than the x-coordinate.

The points that line m represent would be:

Point E  [tex](13, 3)[/tex]

Point B  [tex](6, -4)[/tex]

Point D  [tex](2, -8)[/tex]

The points signalled by line n are as follows:

Point A [tex](-2, 4)[/tex]

Point B  [tex](6, -4)[/tex]

Point C  [tex](12, -10)[/tex]

Now, if we solve for lines

Line m

[tex]x_{1} + y_{1} \\= 13 + 3\\= 16[/tex]

While for Line n

Point A

[tex](x_{1} + y_{1}) = (-2 + 4) \\= 2[/tex]

Point B

[tex]x_{2} + y_{2} = 6 + (-4) \\= 2[/tex]

Thus, the correct match would be as above.

Learn more about "Coordinates" here:

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Jordan has test scores of 70,70,79, 85 and 96. What is the median score?

Answers

Answer:

They are already in order

70, 70, 79, 85, 96

the middle one is 79, meaning 79 is the median.

Step-by-step explanation:

un juego de 4 dados tiene una valor de 1500 pesos ¿cual es el valor de cada dado si todos cuestan lo mismo

Answers

Answer: 375

Step-by-step explanation: 1500 % 4 = 375

PD: que caros dados!

5th grade math. Correct answer will be marked brainliest.

Answers

Answer:

1. 44.3

2. 4.43

3. 0.443

Step-by-step explanation:

Answer:

the 2nt one is also 4.43, and the third one is 2.215 i think

Step-by-step explanation:

I want the answer only.

Answers

25....….......................

What is the equation of the line that is parallel to the
given line and has an x-intercept of -3?

Answers

Answer:

the second option

Step-by-step explanation:

which of the following is the smallest prime number greater than200?

Answers

Answer:

100 or it is 300........

Step-by-step explanation:

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

a + b = 0
which of these is equal to b?

Answers

Answer:

b is equal to negative a and a is also equal to negative b

Step-by-step explanation:

Ratios Pic added Help plz

Answers

Answer:

24:16

skittles : M&Ms

Step-by-step explanation:

Answer:

3:2

Step-by-step explanation:

Well, the total number of pieces of candy is 40. 24 of them are skittles so the remaining 16 would be M&M's. You would write the ratio of skittles to M&M's as 24:16 and then we need to simplify and so the simplified answer is 3:2. (Haven't done these in a while so it might be wrong)

Directions: Match the slope and y-intercept values to the correct boxes below.

anwser. -3,3,1/3, - 1/3 ill give brainlyest to whohas the right awnser and 18 points

Answers

i think this is what you’re asking for... you don’t need the fractions!

MARK BRAINLYIST
The graph shows the distance, y, that a car traveled in x hours:

A graph is shown with x axis title as Time in hours. The title on the y axis is Distance Traveled in miles. The values on the x axis are from 0 to 5 in increments of 1 for each grid line. The values on the y axis are from 0 to 125 in increments of 25 for each grid line. A line is shown connecting ordered pairs 1, 25 and 2, 50 and 3, 75 and 4, 100. The title of the graph is Rate of Travel.

What is the rate of change for the relationship represented in the graph?

fraction 1 over 50
fraction 1 over 25
25
50

Answers

Answer:

25

Step-by-step explanation:

This is a straight line: y = 25x

The rate of change is the slope, i.e., 25

A theater production group is making frames to support wall-like props. Three-foot beams form right triangles with 10-foot beams to allow them to stand, as shown in the image.

A right triangle is shown. The lengths of the 2 sides are 10 feet and 3 feet. The angle opposite to side with length 3 feet is x.

What is x, the angle at which the diagonal beam meets the 10-foot beam at the top of the frame?

16.7°
17.5°
72.5°
73.3°

Answers

Answer:

Step-by-step explanation:

Hence option B is correct.

What is trigonometric function ?

a function of an arc or angle defined in terms of the ratios of pairs of sides of a right-angled triangle (such as sine, cosine, tangent, cotangent, secant, or cosecant).

How to solve?

In the figure it can be seen the perpendicular value =10 feet

and ,the base=3 feet,

tan(x)=10/3

tan(x)=3.33

x=73.3

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Suppose you are hired by the STAR Lab to analyze vehicle arrivals at the right lane of the Evergreen Point Bridge on Westbound SR-520 for the period from 12:00am to 4:00am in a weekday. It is known that vehicle arrivals follow a Poisson process at this location and time period. There is a single-loop detector embedded on this lane at the east end of the bridge. Since you do not want to go to the bridge to count vehicles at this time period, you decided to use the loop detector data for the analysis. Of the 720 20-second intervals (the loop detection system stores data every 20 seconds), 508 intervals were identified to have at least one vehicle detected. Assume the loop detector is free of error. Please estimate the vehicle arrival rate (vehicles per second) for this lane. With the estimated arrival rate, please calculate the probability of having three or more vehicles detected in a 20-second interval and the probability of having a headway shorter than 10 seconds. [15 points]

Answers

Answer:

0.126

Step-by-step explanation:

Given :

Total time interval = 720

Number of interval in which one vehicle is detected =508

Proportion of atleast one detected vehicle :

508 / 720 = 0.7056

The mean arrival rate per second :

P(x ≥ 3) = 1 - P(x ≤ 3)

P(x ≥ 3) =1 - [p(x =0) + p(x = 1) + p(x =2) + p(x = 3)]

P(x ≥ 3) = 1 - 0.8745

P(x ≥ 3) = 0.1255

P(x ≥ 3) = 0.126

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