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Alexandra [31]
2 years ago
5

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.
Mathematics
1 answer:
DIA [1.3K]2 years ago
3 0

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.

<h3>What is an Equation ?</h3>

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.

To know more about Equation

brainly.com/question/10413253

#SPJ1

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Read 2 more answers
Algebra 1 Please help! thank u sm
olga_2 [115]

Answer:

1. Slyvia is wrong. You treat the numbers normally when dividing the left side, so 3.61/4.1 = .88. When dividing the exponents, you subtract the numerator from the denominator, so -11-7 = -18. So, you do have .88 * 10^-18, at first, but when you are working in scientific notation you want the decimal to be greater than so, which requires us to add an additional -1, to make it 8.8 instead of 0.88. This is because we want to move the decimal place left one more time. This results in our final answer being 8.8 * 10^-19, which is not Slyvia's answer.

2. Dylan's answer is correct. He subtracted the exponents correctly, then moved the decimal place over one place towards the left.

3. Ethan is wrong. He added the exponents, instead of subtracting. However, you cannot do this, because when you are dividing exponents, you must subtract.

Step-by-step explanation:

I have this acronym I learned called MADSPM, which has helped me a lot. I never learned it in Algebra, but I wish that they had taught it. Each letter corresponds with an exponent rule. If this makes sense, here is what it stands for:

When you multiply, you add.

When you divide, you subtract.

When there are parentheses, you multiply.

In this case, it was solely division. So, you just need to remember division = subtraction, when it comes to exponents.

Hopefully this helped. If you need me to explain it better, please let me know, and I will try. Thanks much & have a wonderful day!

7 0
3 years ago
Pis possib
Nat2105 [25]

Answer:

x = 350 gallons (amt of 60% solution that must be added)

Step-by-step explanation:

Amt of 60% solution = x gallons ; Amt of active ingredient = 0.6x gallons

Amt of 15% solution = 100 gallons ; Amt of active ingredient = 15 gallons

Amt of 50% solution = 100+x gallons ; Amt of active = 50 + 0.5x gallons

EQUATION:

Active ingredient: 0.60x + 15 = 50 + 0.50x

0.10x = 35

x = 350 gallons (amt of 60% solution that must be added)

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