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1 year ago

12

if the local rate for electrical service is 6cents per kilowatt-hour how much money would be saved in a year by using a dishwash

er 4times per week rather than 6 times per week

1 answer:

dezoksy [38]1 year ago

3 0

Given:

The local rate for electrical service is 6 cents per kilowatt-hour.

We need to know how much money would be saved in a year by using a dishwasher 4times per week rather than 6 times per week

From the table:

The cost of using a dishwasher 4 times per week = $29

The cost of using a dishwasher 6 times per week = $44

So, the saving will be = 44 - 29 = 15

So, the answer will be $15

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Find the dimensions of the open rectangular box of maximum volume that can be made from a sheet of cardboard 21 in. by 12 in. by

a_sh-v [17]

Answer:

Dimension of the box is $16.1\times 7.1\times 2.45$

The volume of the box is 280.05 in³.

Step-by-step explanation:

Given : The open rectangular box of maximum volume that can be made from a sheet of cardboard 21 in. by 12 in. by cutting congruent squares from the corners and folding up the sides.

To find : The dimensions and the volume of the box?

Solution :

Let h be the height of the box which is the side length of a corner square.

According to question,

A sheet of cardboard 21 in. by 12 in. by cutting congruent squares from the corners and folding up the sides.

The length of the box is $L=21-2h$

The width of the box is $W=12-2h$

The volume of the box is $V=L\times W\times H$

$V=(21-2h)\times (12-2h)\times h$

$V=(21-2h)\times (12h-2h^2)$

$V=252h-42h^2-24h^2+4h^3$

$V=4h^3-66h^2+252h$

To maximize the volume we find derivative of volume and put it to zero.

$V'=12h^2-132h+252$

$0=12h^2-132h+252$

Solving by quadratic formula,

$h=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$

$h=\frac{-(-132)\pm\sqrt{132^2-4(12)(252)}}{2(12)}$

$h=\frac{132\pm72.99}{24}$

$h=2.45,8.54$

Now, substitute the value of h in the volume,

$V=4h^3-66h^2+252h$

When, h=2.45

$V=4(2.45)^3-66(2.45)^2+252(2.45)$

$V\approx 280.05$

When, h=8.54

$V=4(8.54)^3-66(8.54)^2+252(8.54)$

$V\approx -170.06$

Rejecting the negative volume as it is not possible.

Therefore, The volume of the box is 280.05 in³.

The dimension of the box is

The height of the box is h=2.45

The length of the box is $L=21-2(2.45)=16.1$

The width of the box is $W=12-2(2.45)=7.1$

So, Dimension of the box is $16.1\times 7.1\times 2.45$

6 0

3 years ago

What’s the least common denominator of 8,12

IceJOKER [234]

Answer: 24

Step-by-step explanation:

One way to find the least common multiple of two numbers is to first list the prime factors of each number. Then multiply each factor the greatest number of times it occurs in either number. If the same factor occurs more than once in both numbers, you multiply the factor the greatest number of times it occurs.

Hope this helps!!! Good luck!!! :)

4 0

3 years ago

Among 18 students in a room, 7 study mathematics, 10 study science, and 10 study computer programming. Also, 3 study mathematics

tatyana61 [14]

Answer:

2 students study none of the subjects.

Step-by-step explanation:

Consider the attached venn diagram. First, we place that 1 student studies the three subjects. Then, we notice that 3 students study math and science, then 2 students study math and science only, since we have 1 that studies the three subjects. In the same fashion, we have that 3 students study Math and computer programming only (since they are 4 in total). Note that since 7 students study math, and we already have 6 students in our count in the math subject this implies that 1 student studies only math (the total number of students inside the math circle must add to 7).

We also have that 4 students study science and computer programming only. Which implies that we must have 3 students that study science only (10 students that study science in total) and 2 students study computer programming (for a total of 10 students). The total number of students that study none is the total number of students (18) minus the amount of students that is inside the circles (16) which is 2.

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2 years ago

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Find the percent of change. Where necessary, round to the nearest percent. Describe the percent of change as a percent of increa

deff fn [24]

70.17543859649122 percent change , rounded would be 70%, it is a 70% increase, as it goes to 57,000 to 97,000

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3 years ago

Please help me on this thank you so much

konstantin123 [22]

The answe is 32 over x

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3 years ago