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Nesterboy [21]
4 years ago
10

Boris is taking a quiz for an online class. For the quiz, the system randomly assigns 2 high-difficulty questions, 7 moderate-di

fficulty questions, and 6 low-difficulty questions. What is the probability that Boris is assigned a moderate-difficulty question first?
Give your answer as a fraction​
Mathematics
1 answer:
Leviafan [203]4 years ago
8 0

Answer:

\frac{7}{15}

Step-by-step explanation:

The probability that Boris is assigned a moderate-difficulty question would be the ratio of number of moderately difficult questions to the number of total questions available.

The quiz consists of 2 high difficulty, 7 moderate difficulty, and 6 low difficulty questions. That is 2 + 7 + 6 = 15 questions in total.

and

the number of moderately difficult questions is 7

Hence the probability would be 7/15

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Find the equation, (f(x) = a(x - h)2 + k), for a parabola containing point (2, -1) and having (4, -3) as a vertex. What is the s
Nataliya [291]

Answer:

f(x)=\frac{1}{2}x^2-4x+5

Step-by-step explanation:

A parabola is written in the form

f(x)=a((x-h)^2+k) (1)

where:

h is the x-coordinate of the vertex of the parabola

ak is the y-coordinate of the vertex of the parabola

a is a scale factor

For the parabola in the problem, we know that the vertex has  coordinates (4,-3), so we have:

h=4 (2)

ak=-3

From this last equation, we get that a=\frac{-3}{k} (3)

Substituting (2) and (3) into (1) we get the new expression:

f(x)=-\frac{3}{k}((x-4)^2+k) = -\frac{3}{k}(x-4)^2 -3 (4)

We also know that the parabola  contains the point (2,-1), so we can substitute

x = 2

f(x) = -1

Into eq.(4) and find the value of k:

-1=-\frac{3}{k}(2-4)^2-3\\-1=-\frac{3}{k}\cdot 4 -3\\2=-\frac{12}{k}\\k=-\frac{12}{2}=-6

So we also get:

a=-\frac{3}{k}=-\frac{3}{-6}=\frac{1}{2}

So the equation of the parabola is:

f(x)=\frac{1}{2}((x-4)^2 -6) (5)

Now we want to rewrite it in the standard form, i.e. in the form

f(x)=ax^2+bx+c

To do that, we simply rewrite (5) expliciting the various terms, we find:

f(x)=\frac{1}{2}((x^2-8x+16)-6)=\frac{1}{2}(x^2-8x+10)=\frac{1}{2}x^2-4x+5

6 0
3 years ago
Need help ASAP!!! Will mark brainliest
Papessa [141]

A=148°

B=148°

Step-by-step explanation:

180-38=148°

because A and B are equal, they're both 148°

7 0
3 years ago
Write the equation of a circle for which the endpoints of a diameter are (-2,-2) and (4,-10)
Maurinko [17]

Answer:

Therefore the required Equation of Circle

x^{2}+y^{2}-2x+12y+12=0

Step-by-step explanation:

Given:

End point of Diameter be

point A( x₁ , y₁) ≡ ( -2 ,-2 )

point B( x₂ , y₂) ≡ ( 4 , -10 )

To Find:

Equation of a circle =?

Solution:

When end points of the Diameter are A( x₁ , y₁) , B( x₂ , y₂). then the Equation of Circle is given as

(x-x_{1})(x-x_{2})+(y-y_{1})(y-y_{2})=0

Substituting the end point are

(x-(-2))(x-4)+(y-(-2))(y-(-10))=0\\(x+2))(x-4)+(y+2))(y+10))=0\\

Applying Distributive Property we get

x^{2} -2x-8+y^{2}+12y+20 =0\\\\x^{2}+y^{2}-2x+12y+12=0

Therefore the required Equation of Circle

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6 0
3 years ago
Convert to a fraction 12 3\100​
sashaice [31]

Answer:

1203/100

Step-by-step explanation:

12 times 100 equals 1200 plus three equals 1203/100

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3 years ago
Hillary is making a blanket for her mom. Three fourths of the blanket is green and the rest is yellow. Two thirds of the yellow
Leviafan [203]

Answer:

1/6

Step-by-step explanation:

Hillary is making a blanket for her mom.

Let the total blanket = 1

Three-fourths of the blanket is green and the rest is yellow.

The fraction for the rest(yellow portion) = 1 - 3/4

The Lowest Common Denominator is 4

Hence,

4 - 3 /4 = 1/4

Two-thirds of the yellow part has her name on it.

The fraction of the blanket that will have her name on it is calculated as

2/3 of 1 /4

= 2/3 × 1/4

= 1/6

4 0
3 years ago
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