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Dmitrij [34]
3 years ago
9

Samantha is trying to determine how she can save money by cutting her electricity bill. She is currently on a standard use plan

for electricity and pays 8.5 cents per kWh. She keeps track of when she uses electricity and is thinking about switching to an interval use plan for electricity which costs 2 cents per kWh for off-peak use and 13 cents per kWh for on-peak use. Off-peak hours are from 8PM - 8AM and on-peak hours are from 8AM - 8PM. Below is the chart of her electricity usage:
Samantha’s Electricity Usage Per Month
1100 kWh between 8PM and 8AM
800 kWh between 8AM and 8PM

Explain and justify which plan would best suit her needs.
a.
Samantha should not switch to the interval use plan, which would cost $126.00 more per month.
b.
Samantha should switch to the interval use plan, which would save her $126.00 per month.
c.
Samantha should switch to the interval use plan, which would save her $35.50 per month.
d.
Samantha should not switch to the interval use plan, which would cost $35.50 more per month.
Mathematics
1 answer:
Harman [31]3 years ago
7 0

Answer:

Step-by-step explanation:

The first step is to save the money the second step is when the bill comes out to pay it right away and then the third one is to do it correctly

You might be interested in
The time (in number of days) until maturity of a certain variety of tomato plant is Normally distributed with mean μ. You select
VLD [36.1K]

Answer: 60.93 < μ < 69.07

Step-by-step explanation: The true mean of a set of data is between an interval of values with a percentage of precision, e.g., a <u>99% confidence interval</u> means we are 99% confident the true mean is between the lower and upper limits.

To find the interval, use

x±z\frac{s}{\sqrt{n}}

z is z-score related to the % of confidence level

In this case, a 99% confidence interval is 2.576

x is sample mean

Calculating:

x=\frac{63+69+62+66}{4}

x = 65

65±2.576\frac{3.16}{\sqrt{4}}

65±4.07

Confidence Interval: 60.93 < μ < 69.07

Meaning that we are 99% sure the population means is between 60.93 and 69.07.

7 0
3 years ago
Help find zeros for 9 and 10
Bingel [31]
<span><span> x4-10x2+9=0</span> </span>Four solutions were found :<span> x = 3 x = -3 x = 1 x = -1</span>

Step by step solution :<span>Step  1  :</span>Skip Ad
<span>Equation at the end of step  1  :</span><span> ((x4) - (2•5x2)) + 9 = 0 </span><span>Step  2  :</span>Trying to factor by splitting the middle term

<span> 2.1 </span>    Factoring <span> x4-10x2+9</span> 

The first term is, <span> <span>x4</span> </span> its coefficient is <span> 1 </span>.
The middle term is, <span> <span>-10x2</span> </span> its coefficient is <span> -10 </span>.
The last term, "the constant", is  <span> +9 </span>

Step-1 : Multiply the coefficient of the first term by the constant <span> <span> 1</span> • 9 = 9</span> 

Step-2 : Find two factors of   9  whose sum equals the coefficient of the middle term, which is  <span> -10 </span>.

<span>     -9   +   -1   =   -10   That's it</span>


Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above,  -9  and  -1 
                     <span>x4 - 9x2</span> - <span>1x2 - 9</span>

Step-4 : Add up the first 2 terms, pulling out like factors :
                    <span>x2 • (x2-9)</span>
              Add up the last 2 terms, pulling out common factors :
                     1 • <span>(x2-9)</span>
Step-5 : Add up the four terms of step 4 :
                    <span>(x2-1)  •  (x2-9)</span>
             Which is the desired factorization

<span>Trying to factor as a Difference of Squares : </span>

<span> 2.2 </span>     Factoring: <span> x2-1</span> 

Theory : A difference of two perfect squares, <span> A2 - B2  </span>can be factored into <span> (A+B) • (A-B)

</span>Proof :<span>  (A+B) • (A-B) =
         A2 - AB + BA - B2 =
         A2 <span>- AB + AB </span>- B2 = 
        <span> A2 - B2</span>

</span>Note : <span> <span>AB = BA </span></span>is the commutative property of multiplication. 

Note : <span> <span>- AB + AB </span></span>equals zero and is therefore eliminated from the expression.

Check : 1 is the square of 1
Check : <span> x2  </span>is the square of  <span> x1 </span>

Factorization is :       (x + 1)  •  (x - 1) 

<span>Trying to factor as a Difference of Squares : </span>

<span> 2.3 </span>     Factoring: <span> x2 - 9</span> 

Check : 9 is the square of 3
Check : <span> x2  </span>is the square of  <span> x1 </span>

Factorization is :       (x + 3)  •  (x - 3) 

<span>Equation at the end of step  2  :</span> (x + 1) • (x - 1) • (x + 3) • (x - 3) = 0 <span>Step  3  :</span>Theory - Roots of a product :

<span> 3.1 </span>   A product of several terms equals zero.<span> 

 </span>When a product of two or more terms equals zero, then at least one of the terms must be zero.<span> 

 </span>We shall now solve each term = 0 separately<span> 

 </span>In other words, we are going to solve as many equations as there are terms in the product<span> 

 </span>Any solution of term = 0 solves product = 0 as well.

<span>Solving a Single Variable Equation : </span>

<span> 3.2 </span>     Solve  :    x+1 = 0<span> 

 </span>Subtract  1  from both sides of the equation :<span> 
 </span>                     x = -1 

<span>Solving a Single Variable Equation : </span>

<span> 3.3 </span>     Solve  :    x-1 = 0<span> 

 </span>Add  1  to both sides of the equation :<span> 
 </span>                     x = 1 

<span>Solving a Single Variable Equation : </span>

<span> 3.4 </span>     Solve  :    x+3 = 0<span> 

 </span>Subtract  3  from both sides of the equation :<span> 
 </span>                     x = -3 

<span>Solving a Single Variable Equation : </span>

<span> 3.5 </span>     Solve  :    x-3 = 0<span> 

 </span>Add  3  to both sides of the equation :<span> 
 </span>                     x = 3 

Supplement : Solving Quadratic Equation Directly<span>Solving <span> x4-10x2+9</span>  = 0 directly </span>

Earlier we factored this polynomial by splitting the middle term. let us now solve the equation by Completing The Square and by using the Quadratic Formula 

<span>Solving a Single Variable Equation : </span>

Equations which are reducible to quadratic :

<span> 4.1 </span>    Solve  <span> x4-10x2+9 = 0</span>

This equation is reducible to quadratic. What this means is that using a new variable, we can rewrite this equation as a quadratic equation Using  w , such that <span> w = x2</span>  transforms the equation into :
<span> w2-10w+9 = 0</span>

Solving this new equation using the quadratic formula we get two real solutions :
   9.0000  or   1.0000

Now that we know the value(s) of <span> w</span> , we can calculate <span> x</span>  since <span> x</span> <span> is  </span><span> √<span> w </span></span> 

Doing just this we discover that the solutions of 
  <span> x4-10x2+9 = 0</span>
  are either : 
  x =√<span> 9.000 </span>= 3.00000  or :
  x =√<span> 9.000 </span>= -3.00000  or :
  x =√<span> 1.000 </span>= 1.00000  or :
  x =√<span> 1.000 </span>= -1.00000 

Four solutions were found :<span> x = 3 x = -3 x = 1 x = -1</span>

<span>
Processing ends successfully</span>

5 0
3 years ago
A local store is advertising a shirt on sale for 40% off the original price. The sale price is $21.00. What was the original pri
pishuonlain [190]

Answer:

  $35

Step-by-step explanation:

If $21 is 60% of the original price, then the original price is ...

  21 = 0.60p

  21/0.60 = p = 35

The original price is $35.00.

8 0
3 years ago
Beatrice graphed the relationship between the time (in seconds) since she sent a print job to the printer and the number of page
xxTIMURxx [149]

Given:

Consider the below figure attached with this question.

To find:

The interpretation for x-intercept in this context.

Solution:

In the given graph x-axis represents the second since sending print job and y-axis represents the Pages printed.

At x-axis the y-coordinate is 0. It means the x-axis represents the number of seconds that passed before the printer started printing pages.

Therefore, the correct option is C.

4 0
3 years ago
Please only answer if you 100% sure! Giving brainliest!!
makvit [3.9K]
I believe the first question is B:advertisement

I believe the second question is C: mass-media

I believe the third question is D: all of these are correct

I believe the fourth question is D: incentive

I believe the fifth question is A: it is free of bias


Hope this helps you have a great day!!!!!!
3 0
2 years ago
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