Which of the expressions are equivalent to the one below? 7x(6+3)

A population is estimated to have a standard deviation of 9. We want to estimate the population mean within 2, with a 99% level

cupoosta [38]

Answer:

The sample required is $n = 135$

Step-by-step explanation:

From the question we are told that

The standard deviation is $\sigma = 9$

The margin of error is $E = 2$

Given that the confidence level is 99% then the level of significance is mathematically evaluated as

$\alpha = 100-99$

$\alpha = 1 \%$

$\alpha = 0.01$

Next we will obtain the critical value $\frac{\alpha }{2}$ from the normal distribution table(reference math dot armstrong dot edu) , the value is

$Z_{\frac{\alpha }{2} } = Z_{\frac{0.05 }{2} } = 2.58$

The sample size is mathematically represented as

$n = [ \frac{Z_{\frac{\alpha }{2} } * \sigma }{E} ]^2$

substituting values

$n = [ \frac{ 2.58 * 9 }{2} ]^2$

$n = 135$

3 0

3 years ago

A store is selling a mixture of apple granola and blueberry granola for $6.99 per pound. Blueberry granola costs $8.99 per pound

Alik [6]

Answer:the number of pounds of blueberry granola that she should put in the mixture is 10 pounds.

the number of pounds of apple granola that she should put in the mixture is 20 pounds

Step-by-step explanation:

Let x represent the number of pounds of blueberry granola that she should put in the mixture.

Let y represent the number of pounds of apple granola that she should put in the mixture.

She wants to make a 30 pounds mixture. This means that

x + y = 30

A store is selling a mixture of apple granola and blueberry granola for $6.99 per pound. This means that the cost of the 30 pound mixture would be

30 × 6.99 = $209.7

Blueberry granola costs $8.99 per pound and apple granola costs $5.99. This means that

8.99x + 5.99y = 209.7 - - - - - - - - - -1

Substituting x = 30 - y into equation 1, it becomes

8.99(30 - y) + 5.99y = 209.7

269.7 - 8.99y + 5.99y = 209.7

- 8.99y + 5.99y = 209.7 - 269.7

- 3y = - 60

y = - 60/ -3

y = 20

Substituting y = 20 into x = 30 - y, it becomes

x = 30 - 20 = 10 pounds

7 0

3 years ago

-6x+7(1-x)=-4(x-4) if you help thank you so much!!!

salantis [7]

Answer:
-1

Step by step explanation:
Rearrange terms
-6x+7(-x+1)=4(x-4)
Distribute
-6x - 7x + 7 = - 4(x-4)
Combine like terms:
−13+7=−4(−4)
Distribute:
−13+7=−4+16
Subtract 7 from both sides of the equation
−13+7−7=−4+16−7
Simplify
−13=−4+9
Add 4x to both sides of the equation
−13+4=−4+9+4
Simplify
Combine like terms
Combine like terms
−9=9
Divide both sides of the equation by the same term
9x/-9 = 9/-9
Simplify
X= -1

8 0

3 years ago

HELP ME PLS stock worth $60 a share dropped in value by 20% on Monday. Then it dropped again by 10$ the next Tuesday. And finall

fgiga [73]

Answer:

58.90

Step-by-step explanation:

3 0

2 years ago

Which expression represents the distance between the points (11, 4) and (5,8)?

antiseptic1488 [7]

Answer:

$\displaystyle d = 2\sqrt{13}$

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Algebra I

Coordinates (x, y)

Algebra II

Distance Formula: $\displaystyle d = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

Step-by-step explanation:

Step 1: Define

Point (11, 4) → x₁ = 11, y₁ = 4

Point (5, 8) → x₂ = 5, y₂ = 8

Step 2: Find distance d

Simply plug in the 2 coordinates into the distance formula to find distance d

Substitute in points [Distance Formula]: $\displaystyle d = \sqrt{(5-11)^2+(8-4)^2}$
[√Radical] (Parenthesis) Subtract: $\displaystyle d = \sqrt{(-6)^2+(4)^2}$
[√Radical] Evaluate exponents: $\displaystyle d = \sqrt{36+16}$
[√Radical] Add: $\displaystyle d = \sqrt{52}$
[√Radical] Simplify: $\displaystyle d = 2\sqrt{13}$

4 0

3 years ago