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Sliva [168]
2 years ago
13

numa prova de múltipla escolha com 30 questões, o aluno ganha 3 pontos por cada questão que acerta, mas perde 2 pontos por cada

questão que erra. Marcelo resolveu todas as questões dessa prova e conseguiu 50 pontos. Quantas questões ele acertou?
Mathematics
1 answer:
CaHeK987 [17]2 years ago
3 0

Answer:

Marcelo acertou 22 questões.

Step-by-step explanation:

Vamos representar

Questões que acerta = a

Questões que erra = b

a + b = 30 .......... Equação 1

a = 30 - b

o aluno ganha 3 pontos por cada questão que realizar, mas perde 2 pontos por cada questão que ocorrerá.

Matematicamente:

3 × a - 2 × b = 50

3a - 2b = 50 pontos ............. Equação 2

Substitua 30 - b por a na Equação 2

3 (30 - b) - 2b = 50

90 - 3b - 2b = 50

90 - 5b = 50

Colete termos semelhantes

90 - 50 = 5b

5b = 40

b = 40/5

b = 8

Questões que erra = b

Marcelo, portanto, perdeu 8 questões.

Dizem-nos que ele respondeu todas as 30 questões. Portanto, se ele perdeu 8 questões, o número de questões acertadas é representado pela Equação 1

a + b = 30 .......... Equação 1

a + 8 = 30

a = 30 - 8

a = 22 questões.

Portanto, ele acertou 22 questões.

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Answer:

V = 64 and V = 2,048

Step-by-step explanation:

The volume of a cube is found using V = s*s*s. Substitute s = 4.

The volume is V = 4*4*4 = 64.

The volume of the crate is 32 * 64 = 2,048.

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3 years ago
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Likurg_2 [28]

Answer: 2000 tickets were sold

Step-by-step explanation:

8000 divided by 40 percent is 200

6 0
3 years ago
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Please help me out solve it and tell me how you got that answer so I can understand please!
NikAS [45]

The solution for s in the given equation is s = C-nD

The question seems to be incomplete

Here is the complete question:

Solve for s in this equation D= \frac{C-s}{n}   Depreciation.

To solve for s, that means we should make s the subject of the equation

From the given equation,

D= \frac{C-s}{n}

To solve for s, first multiply both sides by n to clear the fraction

We get

n\times D= n \times \frac{C-s}{n}

Then,

nD = C - s

Now, add s to both sides

nD + s= C - s+s

nD+s = C

Then, subtract nD from both sides

nD-nD+s = C-nD

∴ s = C-nD

Hence, the solution for s in the given equation is s = C-nD

Learn more here: brainly.com/question/21406377

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Here is a diagram and its corresponding equation. Find the solution to the equation.
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4(x + 7) = 38

Since there is no operation sign between the 4 and parenthesis, it makes it an automatic multiplication problem.

You would use distributive property to multiply each which should leave your equation looking like this afterwards:

4x + 28 = 38
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You would then solve it like a two step equation,

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2. 38 - 28 = 10

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10 divided by 4 = 2.5

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We can recheck our work by substituting in the value of x.

4(2.5 + 7) = 38

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When we substituted in the value, it gave us the correct inequality.

Therefore,
x = 2.5
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2 years ago
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