Problem

Which of the following ratios is equivalent to 5/20. select all that apply

Rama09 [41]

The ratios that are equivalent to 5/20ths, are 1/4th and 25/100ths.

7 0

3 years ago

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Which expression represents the product of 83 and x

avanturin [10]

The product means multiplication.

An expression does not have an equal sign.

83 * x
83x

Answer: 83x

4 0

3 years ago

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Many smartphones, especially those of the LTE-enabled persuasion, have earned a bad rap for exceptionally bad battery life. Batt

BartSMP [9]

Answer:

Null hypothesis: the variance in hours of usage for talking is not greater than the the variance in hours of usage for internet.

$H_o$ : $\sigma _1 ^2 \leq \sigma _2^2$

Alternative hypothesis: the variance in hours of usage for talking is greater than the the variance in hours of usage for internet.

$H_a : \sigma_1^2 > \sigma_2^2$

$\mathbf{s_ 1 =16.11}$

$\mathbf{s_2 = 7.98}$

Step-by-step explanation:

Let $x_1$ and $x_2$ be the two variables that represents the battery life in hours for talking usage and battery life in hours for internet usage respectively.

The hypothesis can be formulated as:

Null hypothesis: the variance in hours of usage for talking is not greater than the the variance in hours of usage for internet.

$H_o$ : $\sigma _1 ^2 \leq \sigma _2^2$

Alternative hypothesis: the variance in hours of usage for talking is greater than the the variance in hours of usage for internet.

$H_a : \sigma_1^2 > \sigma_2^2$

The standard deviation for the battery usage for talking is :

$\bar x_1 = \dfrac{1}{n_1} \sum x_i \\ \\ \bar x_1 = \dfrac{1}{12}(35.8 +22.4+...+35.5) \\ \\ \bar x_1 = \dfrac{241.2}{12} \\ \\ \bar x_1 =20.1$

The standard deviation Is:

$s_ 1 = \sqrt{\dfrac{1}{n_1-1}\sum (x{_1i}-\bar x_i)^2}$

$s_ 1 = \sqrt{\dfrac{1}{12-1}\sum (35.8- 20.1)^2+ (35.5-20.1)^2}$

$s_ 1 = \sqrt{259.568}$

$\mathbf{s_ 1 =16.11}$

The standard deviation for the battery life usage for the internet is :

$\bar x_2 = \dfrac{1}{n_2} \sum x_{2i}$

$\bar x_2 = \dfrac{1}{10} (24.0+12.5+36.4+...+4.7})$

$\bar x_2 = \dfrac{115}{10}$

$\bar x_2 = 11.5$

Thus; the standard deviation is:

$s_2 = \sqrt{\dfrac{1}{n_2-1}(x_{2i}- \bar x_2)^2}$

$s_2 = \sqrt{\dfrac{1}{10-1}(24-11.5)^2+(4.7-11.5)^2}$

$s_2 = \sqrt{63.60}$

$\mathbf{s_2 = 7.98}$

4 0

3 years ago

7.4.PS-6

Sedaia [141]

Answer:

The area of the given polygon is:

232 cm^2

Step-by-step explanation:

To find the area of the polygon in the picture, you can divide the polygon in three rectangles: a 3 cm by 14 cm, a 5 cm by 14 cm rectangle, and the last rectangle must have a base of 12 cm (20 cm - 3 cm - 5 cm), and a height of 10 cm (14 cm - 4 cm). We can calculate the area of the rectangles with the formula below:

Area of a rectangle = Base * height

Now, we're gonna replace the measurements in the formula.

First rectangle:

Area of a rectangle = 3 cm * 14 cm
Area of a rectangle = 42 cm^2

Second rectangle:

Area of a rectangle = 5 cm * 14 cm
Area of a rectangle = 70 cm^2

Third rectangle:

Area of a rectangle = 12 cm * 10 cm
Area of a rectangle = 120 cm^2

By last, we must add the area of the rectangles:

Area of the polygon = 42 cm^2 + 70 cm^2 + 120 cm^2
Area of the polygon = 232 cm^2

As you can see, the area of the polygon in the picture is 232 cm^2.

5 0

3 years ago

Find the equation of the quadratic function with zeros -1 and 1 and a vertex at (0,-4)

Stolb23 [73]

The equation is f(x) = 4x^2 - 4.

You can find this by using an equation with parenthesis that equal each of the zeros.

f(x) = (x - 1)(x + 1)

Now, this equation will not give us the vertex that we're looking for. So, we must add a constant being multiplied to the front of it.

f(x) = c(x - 1)(x + 1)

Now we can find the constant by putting our vertex into the equation and solving.

f(x) = c(x - 1)(x + 1)

-4 = c(0 - 1)(0 + 1)

-4 = c(-1)(1)

-4 = -1c

c = 4

Now we put the c into the original equation and solve for standard form.

f(x) = 4(x - 1)(x + 1)

f(x) = 4(x^2 - 1)

f(x) = 4x^2 - 4

8 0

3 years ago