Ms. Nina has 10 lbs of 25% sugar syrup. How much water does she need to add to make 10% sugar syrup

The Polk Company reported that the average age of a car on U.S. roads in a recent year was 7.5 years. Suppose the distribution o

Svetlanka [38]

Answer:

The standard deviation of car age is 2.17 years.

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

68% of the measures are within 1 standard deviation of the mean.

95% of the measures are within 2 standard deviation of the mean.

99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean = 7.5

(a) If 99.7% of the ages are between 1 year and 14 years, what is the standard deviation of car age?

This means that 1 is 3 standard deviations below the mean and 14 is 3 standard deviations above the mean.

So

$14 = 7.5 + 3\sigma$

I want to find $\sigma$

$3\sigma = 6.5$

$\sigma = \frac{6.5}{3}$

$\sigma = 2.17$

The standard deviation of car age is 2.17 years.

8 0

2 years ago

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Find the smallest relation containing the relation {(1, 2), (1, 4), (3, 3), (4, 1)} that is:

professor190 [17]

Answer:

Remember, if B is a set, R is a relation in B and a is related with b (aRb or (a,b))

1. R is reflexive if for each element a∈B, aRa.

2. R is symmetric if satisfies that if aRb then bRa.

3. R is transitive if satisfies that if aRb and bRc then aRc.

Then, our set B is $\{1,2,3,4\}$ .

a) We need to find a relation R reflexive and transitive that contain the relation $R1=\{(1, 2), (1, 4), (3, 3), (4, 1)\}$

Then, we need:

1. That 1R1, 2R2, 3R3, 4R4 to the relation be reflexive and,

2. Observe that

1R4 and 4R1, then 1 must be related with itself.
4R1 and 1R4, then 4 must be related with itself.
4R1 and 1R2, then 4 must be related with 2.

Therefore $\{(1,1),(2,2),(3,3),(4,4),(1,2),(1,4),(4,1),(4,2)\}$ is the smallest relation containing the relation R1.

b) We need a new relation symmetric and transitive, then

since 1R2, then 2 must be related with 1.
since 1R4, 4 must be related with 1.

and the analysis for be transitive is the same that we did in a).

Observe that

1R2 and 2R1, then 1 must be related with itself.
4R1 and 1R4, then 4 must be related with itself.
2R1 and 1R4, then 2 must be related with 4.
4R1 and 1R2, then 4 must be related with 2.
2R4 and 4R2, then 2 must be related with itself

Therefore, the smallest relation containing R1 that is symmetric and transitive is

$\{(1,1),(2,2),(3,3),(4,4),(1,2),(1,4),(2,1),(2,4),(3,3),(4,1),(4,2),(4,4)\}$

c) We need a new relation reflexive, symmetric and transitive containing R1.

For be reflexive

1 must be related with 1,

2 must be related with 2,

3 must be related with 3,

4 must be related with 4

For be symmetric

since 1R2, 2 must be related with 1,
since 1R4, 4 must be related with 1.

For be transitive

Since 4R1 and 1R2, 4 must be related with 2,
since 2R1 and 1R4, 2 must be related with 4.

Then, the smallest relation reflexive, symmetric and transitive containing R1 is

$\{(1,1),(2,2),(3,3),(4,4),(1,2),(1,4),(2,1),(2,4),(3,3),(4,1),(4,2),(4,4)\}$

5 0

2 years ago

If 25^x+1 = 125/5^x find the value of x

storchak [24]

Answer:

x =1/3

Step-by-step explanation:

25ˣ⁺¹ = 125/5ˣ

5²⁽ˣ⁺¹⁾ = 5³/5ˣ

5²⁽ˣ⁺¹⁾ = 5³ : 5ˣ

5²⁽ˣ⁺¹⁾ = 5³⁻ˣ

2(x + 1) = 3 - x

2x + 2 = 3 - x

2x + x = 3 - 2

3x = 1

x = 1/3

8 0

2 years ago

Find the average rate of change of the function defined by the following table. x y -2 -5 2 35 6 75 10 115

Pani-rosa [81]

By definition we have that the average rate of change of the function is:

$AVR = \frac{f(x2) - f(x1)}{x2 - x1}$

Evaluating the function for the complete interval we have that the AVR is given by:

$AVR = \frac{115 - (-5)}{10 - (-2)}$

Rewriting we have:

$AVR = \frac{115+5}{10+2}$

Simplifying the expression we have:

$AVR = \frac{120}{12}$

$AVR = 10$

Answer:

the average rate of change of the function defined by the table is:

$AVR = 10$

6 0

2 years ago

Explain how you could write a quadratic function in factored form that would have a vertex with an x-coordinate of 3 and two dis

dem82 [27]

Two distinct roots means two real solutions for x (the parabola needs to cross the x-axis twice)

Vertex form of a quadratic equation: (h,k) is vertex

y = a(x-h)^2 + k

The x of the vertex needs to equal 3

y = a(x-3)^2 + k

In order to have two distinct roots the parabola must be (+a) upward facing with vertex below the x-axis or (-a) downward facing with vertex above the x-axis. Parabolas are symmetrical so for an easy factorable equation make "a" 1 or -1 depending on if you want the upward/downward facing one.

y = (x-3)^2 - 1

Vertex (3,-1) upwards facing with two distinct roots 4 and 2

y = x^2 -6x + 9 - 1

y = x^2 -6x + 8

y = (x - 4)(x - 2)

7 0

2 years ago

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