Thalia, a quiz show contestant, answered 20 questions. She was awarded 2 points for every correct answer that she gave, but she was penalized 1 point for every incorrect answer. In the end, Thalia had a total of 28 points. In order to determine the number of correct and incorrect answers that she gave, a viewer at home used the system of linear equations x + y = 20 and 2 x + y = 28, with x being the number of correct answers and y being the number of incorrect answers. The viewer solved the system by using the linear combination method as shown.

x + y = 20. + StartFraction Negative 2 x minus y = negative 28 over Negative x = negative 8 EndFraction. StartFraction negative x Over negative 1 EndFraction = StartFraction negative 8 Over negative 1 EndFraction. X = 8.
8 + y = 20. 8 + y minus 8 = 20 minus 8. y = 12.

The viewer calculated that the contestant answered 8 questions correctly and 12 questions incorrectly. What went wrong?
The viewer mistakenly determined that one of the equations in the system should be x + y = 20.Instead modifications should have been made before applying the equation.
The viewer mistakenly determined that one of the equations in the system should be 2 x + y = 28. Instead modifications should have been made before applying the equation.
The viewer multiplied the equation 2 x + y = 28 by –1 incorrectly.
The viewer added the equations x + y = 20 and Negative 2 x minus y = negative 28 incorrectly.

Answers

Answer 1

The viewer mistakenly determined that one of the equations in the system should be 2 x + y = 28. Instead modifications should have been made before applying the equation.

What is an Equation ?

An equation is a mathematical statement formed when two algebraic expressions are equated using an equal sign.

Total Questions = 20

Total Points = 28

Correct Answers = +2 points

Incorrect Answers = -1 point

The viewer represents the correct answers with x and the incorrect ones with y.

x+y = 20

for every correct answers 2 points;

and for every incorrect answers, -1 point

This can be written as

2x-y = 28

The viewer's mistake is that; instead of subtracting total incorrect points from the correct points, the viewer added them together;

now

2x-y = 28

x+y = 20

On adding the equations

]3x = 48

x = 16

y = 4

This means that the contestant answered 16 questions correctly and 4 questions incorrectly

The viewer mistakenly determined that one of the equations in the system should be 2 x + y = 28.

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Related Questions

What is the y-intercept of the equation of the line that is perpendicular to the line y = 3/5x + 10 and passes through the point (15, –5)? The equation of the line in slope-intercept form is y =-5/3 x + ____

Answers

Substituting into point-slope form,

[tex]y+5=-\frac{5}{3}(x-15)\\\\y+5=-\frac{5}{3}x+25\\\\\boxed{y=-\frac{5}{3}x+20}[/tex]

What are the measures of ∠1 and ∠2? Show your work or explain your answers.

Answers

Answer:

angle 1 is 105degrees and angle 2 is 75degrees

Step-by-step explanation:

The angle below angle 2, presumably angle 6, is also 75 degrees since line c and line d are parallel. If angle 2 is 75 degrees then we know that angle 1 is 105 degrees since both angles equal a straight line and a straight line has 180 degrees.

The sequence an = 1(3)n − 1 is graphed below: coordinate plane showing the points 1, 1; 2, 3; and 3, 9 Find the average rate of change between n = 1 and n = 3. (6 points)

Answers

Answer:

4

Step-by-step explanation:

[tex] \frac{9 - 1}{3 - 1} = 4[/tex]

The average rate of change on the interval [3, 9] will be 4.

How to find the average rate of change?

The average rate of change between two points is given by the slope formula:

 m = average rate of change = (y2 -y1)/(x2 -x1)

The sequence an = 1(3)n − 1 is graphed below:

 m = (9 -1)/(3 -1) = 8/2

 m = 4

The average rate of change on the interval [3, 9] will be 4.

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A rectangular prism and a cylinder both have a height of 8m, and their cross-sectional areas are equal at every level parallel to their respective bases.

Complete the steps to find the prism.

Answers

1) [tex]V=lwh=5(x)(8)=\boxed{40x}[/tex]

2) [tex]V=\pi r^{2}h=(\pi)(3^{2})(8)=\boxed{72}\pi[/tex]

3) [tex]40x=72\pi\\\\x=\frac{72\pi}{40} \approx \boxed{5.7}[/tex]

A cell phone towerbcast a shadow that is 40 feet long . An 10- foot- tall stop sign located near the tower casts a shadow that is 8 feet long. How tall is the cell phone tower?

Answers

Using proportions, considering the relation between the height and the shadow, it is found that the cell phone tower is 50 feet.

What is a proportion?

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

When the shadow is of 8 feet, the height is of 10 feet. What is the height when the shadow is of 40 feet? The rule of three is:

8 feet - 10 feet

40 feet - h feet

Applying cross multiplication:

8h = 10 x 40

Simplifying by 8:

h = 10 x 5 = 50 feet.

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What error did Lucia make?

Answers

Answer:

See below

Step-by-step explanation:

She combined 3x and - 9x   incorrectly

  she should have gotten  - 6 x       not  - 12 x

the height of a toy rocket

Answers

16t2 + 48tf = 16t2 + 48t

The second one is the answer

Plato trigonometry is crazy

Answers

Answer:

The answer is A. 21

i hope this can help you! :)

Answer:

a)21

-step explanation:

What was the initial quantity of vanadium-49, which has a half-life of 330 days, if after 540 days there is a 1,750 g sample remaining?a.)5,440.42g b.)3,500g C.) 8,700g d.)2,863.63g e.)98g

Answers

Answer:

  (a)  5440.42 g

Step-by-step explanation:

The amount remaining (Q) is given in terms of the initial amount (Q₀) by the exponential decay formula ...

  Q = Q₀(1/2)^(t/330) . . . . . where t is in days

__

The amount after 540 days is ...

  1750 g = Q₀(1/2)^(540/330) = 0.321666Q₀

  Q₀ = (1750 g)/(0.321666) ≈ 5440.42 g

The initial quantity was about 5440.42 grams.

The figure below shows parallel lines cut by a transversal:

A pair of parallel lines is shown with arrowheads on each end. A transversal cuts through these two lines. An angle formed between the top parallel line and the transversal on the inner left side is marked 1. Another angle formed between the bottom parallel line and the transversal on the inner right side is marked 2.

Which statement is true about ∠1 and ∠2?

∠1 and ∠2 are congruent because they are a pair of adjacent angles.
∠1 and ∠2 are complementary because they are a pair of adjacent angles.
∠1 and ∠2 are congruent because they are a pair of alternate interior angles.
∠1 and ∠2 are complementary because they are a pair of alternate interior angles.

Answers

∠1 and ∠2 are congruent because they are a pair of alternate interior angles , Option C is the right answer.

What are Parallel Lines ?

When two lines do not meet at any point and the distance between them remains constant , then the two lines are called parallel to each other .

It is given that the parallel lines are cut by a transversal and the angles are marked

The angle 1 and angle 2 are congruent because they are pair of alternate interior angles .

Therefore Option C is the right answer.

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Solve the equation on the
interval [0, 2π).
√2 cos x - 1 = 0

Answers

Answer:

Step-by-step explanation:

[tex]\sqrt{2} cos x-1=0\\cos x=\frac{1}{\sqrt{2} } =cos (\frac{\pi }{4} ),cos (2\pi -\frac{\pi }{4} )\\cos x=cos(2n\pi +\frac{\pi }{4} ),cos(2n\pi +\frac{7\pi }{4} )\\x=2n\pi +\frac{\pi }{4} ,2n\pi +\frac{7\pi }{4} \\n=0\\x=\frac{\pi }{4} ,\frac{7\pi }{4}[/tex]

if n × 18 = ½ find n

Answers

n=1/2/18
n=1/2 multiplied 1/18
n=1/36

Answer:

n = [tex]\frac{1}{36}[/tex]

Step-by-step explanation:

n × 18 = [tex]\frac{1}{2}[/tex]

To find the value of n we have to divide both sides by 18.

Let us solve it now.

18n = [tex]\frac{1}{2}[/tex]

[tex]\frac{18n}{18}[/tex] = [tex]\frac{1}{2}[/tex] ÷ 18

n =  [tex]\frac{1}{2}[/tex] ÷ 18

n = [tex]\frac{1}{2}[/tex] ÷ [tex]\frac{18}{1}[/tex]

n =  [tex]\frac{1}{2}[/tex] × [tex]\frac{1}{18}[/tex]

n = [tex]\frac{1}{36}[/tex]

find the missing number in ?/4 = 27/36​

Answers

[tex]\text{First I would recommend replacing the question mark with x}\\\text{We have two ratios, }\\\text{and we need to solve that hard-looking equation}\\\text{in terms of x}[/tex]

[tex]\rule{300}{1.7}[/tex]

[tex]\text{We can multiply x times 36:: 36x}\\\text{We can multiply 4 times 27:: 108}[/tex]

[tex]\rule{300}{1.7}[/tex]

[tex]\text{Now it's easier to solve for x:: 36x=108; x=3}\\\text{ (we divided by 36 on both sides of the = sign)}[/tex]

[tex]\rule{300}{1.7}[/tex]

[tex]\text{The missing number is 3}[/tex]

Help me with this question please and thank you!! :)

Answers

[tex]A \cup B[/tex] represents the set that contains all the elements that are in at least one of the sets, so [tex]A \cup B=\{1, 2, 5, 6, 7, 8, 9, 10, 12, 16, 18, 19, 20, 21, 22, 23, 25\}[/tex].

We want the complement of this set (in other words, the set with all the elements in the universal set but not in the given set).

This set is {3, 4, 11, 13, 14, 15, 17, 24}

URGENT + 20 Points! The regression equation for water being poured into a large, cone-shaped cistern is In(volume) = -1.327 +2.993 In(Time). What is the predicted volume for a time of 12 seconds?

- There is a line above "(volume)"


1.810 cm3

6.110 cm3

34.589 cm3

450.485 cm3

Answers

The predicted volume for a time of 12 seconds of the large, cone-shaped cistern is; V = 450.485 cm³

How to Solve Regression Equations?

We are given the regression equation;

In V = -1.327 + 2.993 In T

Where;

V is volume

T is time

At T = 12, we have;

In V = -1.327 + 2.993 In 12

In V =  -1.327 + 7.4373

In V = 6.1103

V = e^(6.1103)

V = 450.485 cm³

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f(x) = x² + (k-6) x +9, k * 0. The roots of the equation f(x) = 0 are a and B. (a) Find, in terms of k, the value of (i) a² + ß² (ii) a² ß² Given that 9(a²+ B²) = 2a²p². find the value of k. (b) (c) Using your value of k, and without solving the equation f(x) = 0. form a quadratic equation, with integer coefficients, which has roots and 33² f ( x ) = x² + ( k - 6 ) x +9 , k * 0 . The roots of the equation f ( x ) = 0 are a and B. ( a ) Find , in terms of k , the value of ( i ) a² + ß² ( ii ) a² ß² Given that 9 ( a² + B² ) = 2a²p² . find the value of k . ( b ) ( c ) Using your value of k , and without solving the equation f ( x ) = 0 . form a quadratic equation , with integer coefficients , which has roots and 33²​

Answers

(a) If [tex]\alpha[/tex] and [tex]\beta[/tex] are roots of [tex]f(x)[/tex], then we can factorize [tex]f[/tex] as

[tex]f(x) = x^2 + (k - 6) x + 9 = (x - \alpha) (x - \beta)[/tex]

Expand the right side and match up coefficients:

[tex]x^2 + (k-6) x + 9 = x^2 - (\alpha + \beta) x + \alpha \beta \implies \begin{cases} \alpha + \beta = -(k-6) \\ \alpha \beta = 9 \end{cases}[/tex]

Now, recall that [tex](x+y)^2 = x^2 + 2xy + y^2[/tex]. It follows that

[tex]\boxed{\alpha^2 + \beta^2} = (\alpha + \beta)^2 - 2\alpha\beta = (-(k-6))^2 - 2\times9 = \boxed{k^2 - 12k + 18}[/tex]

and

[tex]\boxed{\alpha^2\beta^2} = 9^2 = \boxed{81}[/tex]

(b) If [tex]9(\alpha^2+\beta^2) = 2\alpha^2\beta^2[/tex], then

[tex]9 (k^2 - 12k + 18) = 2\times81 \implies 9k^2 - 108k = 0 \implies 9k (k - 12) = 0[/tex]

Since [tex]k\neq0[/tex], it follows that [tex]\boxed{k=12}[/tex].

(c) The simplest quadratic expression with roots [tex]\frac1{\alpha^2}[/tex] and [tex]\frac1{\beta^2}[/tex] is

[tex]\left(x - \dfrac1{\alpha^2}\right) \left(x - \dfrac1{\beta^2}\right)[/tex]

which expands to

[tex]x^2 - \left(\dfrac1{\alpha^2} + \dfrac1{\beta^2}\right) x + \dfrac1{\alpha^2\beta^2}[/tex]

Reusing the identity from (a-i) and the result from part (b), we have

[tex]\left(\dfrac1\alpha + \dfrac1\beta\right)^2 = \dfrac1{\alpha^2} + \dfrac2{\alpha\beta} + \dfrac1{\beta^2} \\\\ \implies \dfrac1{\alpha^2} + \dfrac1{\beta^2} = \left(\dfrac{\alpha + \beta}{\alpha\beta}\right)^2 - \dfrac2{\alpha\beta} = \left(\dfrac{-(k-6)}9\right)^2 - \dfrac29 = \dfrac29[/tex]

We also know from part (a-ii) that [tex]\alpha^2\beta^2=81[/tex].

So, the simplest quadratic that fits the description is

[tex]x^2 - \dfrac29 x + \dfrac1{81}[/tex]

To get one with integer coefficients, we multiply the whole expression by 81 to get [tex]\boxed{81x^2 - 18x + 1}[/tex].

Want to earn 20 points for correct answer CLICK ME

Answers

Answer:

64 is the answer

Step-by-step explanation:

Mark me brainliest answer pls

64 should be the correct answer

In the given figure, ABCD is a parallelogram. Find x, y and z. ​

Answers

Answer:

it is 18 by unknown number

Does this graph show a function explain how you know

Answers

The correct option is Option D: Yes, the graph passes the vertical line test.

The function is a relationship between two distinct sets X and set Y which can be many-one or one-one. here set X is called the domain and set Y is called the codomain.

The vertical line test states that

If we draw a straight vertical line( which is also parallel to the y-axis) and it touches the graph at only one point at all locations, then that relation is said to be a function and this relation will be also one-one.

So here in this function shown in the graph.

If we draw a vertical line parallel to the y-axis in this at any location then it crosses the graph only once. So, it passes vertical line test. And this graph is a function. Therefore option D is correct.

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Write an equation for the transformed logarithm shown below, that passes through (-2,0) and (0,-3)

Answers

Using translation concepts, the equation for the transformed logarithm is given by:

[tex]f(x) = \log{(x + 3)} - 3.48[/tex]

What is a translation?

A translation is represented by a change in the function graph, according to operations such as multiplication or sum/subtraction in it's definition.

The logarithm function is given by:

[tex]f(x) = \log{x}[/tex].

We have that:

It passes through (1,0), and in this problem it passes through (-2,0), that is, it was shifted left 3 units, hence x -> x + 3.

Hence:

[tex]f(x) = \log{x + 3} + b[/tex]

To find the shift up/down, we consider that f(0) = -3, hence:

[tex]-3 = \log{0 + 3} + b[/tex]

[tex]b = -3 - \log{3}[/tex]

b = -3.48.

Hence the function is given by:

[tex]f(x) = \log{x + 3} - 3.48[/tex]

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Uniform Distibution
The mail arrival time to a department has a uniform distribution over 0 to 60 minutes. What is the probability that the mail arrival time is more than 20 minutes on a given day? Answer: (Round to 2 decimal places.)

Answers

Step-by-step explanation:

Let X be the mail arrival time to a department that follows uniform distribution over 0 to 60 minutes.

The probability function of X is:

f

(

x

)

=

1

60

,

0

<

x

<

60

Now, the probability that the mail arrival time is more than 40 minutes on a given day is calculated below:

P

(

X

>

40

)

=

60

40

1

60

d

x

=

[

x

60

]

60

40

After 8 points are added to each score in a sample.
the mean is found to be M = 40. What was the
value for the original mean?

Answers

I think it’s 32 because it’s more simple then it looks! It would just be 40-8??

find the value of x

d:6​

Answers

[tex] \sf{\qquad\qquad\huge\underline{{\sf Answer}}} [/tex]

Let's solve for x ~

[tex]\qquad \sf  \dashrightarrow \: 5x = 3x + 12[/tex]

[ by vertical opposite angle pair ]

[tex]\qquad \sf  \dashrightarrow \: 5x - 3x = 12[/tex]

[tex]\qquad \sf  \dashrightarrow \: 2x = 12[/tex]

[tex]\qquad \sf  \dashrightarrow \: x = 12 \div 2[/tex]

[tex]\qquad \sf  \dashrightarrow \: x = 6[/tex]

Therefore, the correct choice is D. 6

Answer: D) 6

Step-by-Step Solution:

We know, (5x)° and (3x + 12)° are Vertically Opposite Angles and Vertically Opposite Angles are Equal.

Therefore,
5x = 3x + 12
5x - 3x = 12
2x = 12
x = 12/2
=> x = 6

Therefore, x = 6

Hassan put 437.2 grams of brown sugar into a canister. Then he carefully measured out 430.43 grams of it to use in a recipe for cookies. How much brown sugar is left in the canister?

Answers

437.2-430.43=6.77 grams

What is the range of y=sin(x)?

Answers

The range of y = sin(x) is [-1,1]

How to determine the range?

The function is given as:

y = sin(x)

The above function is the parent function of a sine function.

A sine function has a minimum of -1 and a maximum of 1.

This is represented by the interval [-1,1]

Hence, the range of y = sin(x) is [-1,1]

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1 x 1 x 99 x 100 hat is the awnser

Answers

The answer to this equation is 9,900. Why? Well, we can solve this equation in left-to-right format, seeing that there are no brackets, exponents, or parenthesis:

Step One: 1 x 1 = 1. Anything multiplied by one is the same number that was started with.

Step Two: 1 x 99 = 99. Again, anything multiplied by one is the same number that we started with, which in this case was 99.

Step Three: 99 x 100 = 9,900. Because 100 is a power of ten, we could easily find the solution by shifting the digits two places to the left to increase their value. However, if you would like to do it the long way, you could simply write out 100 x 99 and solve it.

Your final answer: 1 x 1 x 99 x 100 = 9,900.

Which of the following is a geometric sequence?
• A. 6, 18, 54, 162
O B. 1, 4, 5, 9, 14
O C. 3, 6, 9, 12, 15
O D. 3, 5, 8, 13, 21

Answers

Answer: A. 6, 18, 54, 162

Step-by-step explanation:

Each term is 3 times the last, meaning the common ratio is 3.

Item 6
A set of books sits on a shelf at a store. This line plot shows the thickness of each book. Juan buys one of the thickest books on the shelf. Min buys the third thinnest book on the shelf.

How much thicker is Juan’s book than Min’s book?

Answers

Answer:

There is no line plot

Step-by-step explanation:

2 and a half(what’s ever size it’s in) I had this question today! Pretty sure there the same but not 100%

If f(x) = 3x − 1 and g(x) = x + 2, find (ƒ– g)(x) ​

Answers

[tex]\quad \huge \quad \quad \boxed{ \tt \:Answer }[/tex]

[tex]\qquad \tt \rightarrow \:2x - 3 [/tex]

____________________________________

[tex] \large \tt Solution \: : [/tex]

[tex]\qquad \tt \rightarrow \: (f - g)(x)[/tex]

[tex]\qquad \tt \rightarrow \: f(x) - g(x)[/tex]

Simple procedure :

[tex]\qquad \tt \rightarrow \: 3x - 1 - (x + 2)[/tex]

[tex]\qquad \tt \rightarrow \: 3x - 1 - x - 2[/tex]

[tex]\qquad \tt \rightarrow \: 3x - x - 1 - 2[/tex]

[tex]\qquad \tt \rightarrow \: 2x - 3[/tex]

Answered by : ❝ AǫᴜᴀWɪᴢ ❞

How many miles per hour does a sneeze travel? 1 10 100 1000

Answers

The average speed of sneeze is about 100 miles per hour.

What is the average speed of sneeze?

The average speed of sneeze is determined from the total distance traveled by the sneeze to the total time of motion of the sneeze.

Averagely a sneeze can travel as fast as 100 miles in an hour, which is equivalent to 44.7 m/s.

Thus, the average speed of sneeze is about 100 miles per hour.

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