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mariarad [96]
4 years ago
8

The Cobb family of Fremont is looking at ways to decrease their home water and energy usage. Their current electric hot-water he

ater raises the water temperature to 140 degree F, which requires 0.20 kWh/gallon at a cost of $0.10/kWh. Each person in the family of four showers once a day for an average of 10 minutes per shower. The shower has a flow rate of 5.0 gallons per minute. a.Calculate the following. Be sure to show all your work and include units with your answers. i)The total amount of water that the family uses per year for taking showers.ii)The annual cost of the electricity for the family showers, assuming that 2.5 gallons per minute of the water used is from the hot-water heater b.The family is considering replacing their current hot-water heater with a new energy-efficient hot-water heater that costs $1,000 and uses half the energy that their current hot-water heater uses. How many days would it take for the new hot-water heater to recover the $1,000 initial cost?
Mathematics
1 answer:
OverLord2011 [107]4 years ago
5 0

Answer:

  ai) 73000 gal/yr

  aii) $730 per year

  b) 1000 days

Step-by-step explanation:

ai) The water usage per day is ...

  (4 showers/day)(10 min/shower)(5 gal/min) = 200 gal/day

Then the usage per year is ...

 (200 gal/day)(365 days/yr) = 73,000 gal/yr

__

aii) The cost of electricity is the cost of heating half the water usage, so is ...

  (0.20 kWh/gal)(1/2)(73,000 gal/yr)($0.10/kWh) = $730/yr

__

b) The current daily cost of electricity for heating water is ...

  ($730/yr)/(365 days/yr) = $2/day

If the cost is cut in half, it will be $1 per day. That means the savings is $1 per day, so it will take 1000 days to recover the $1000 initial cost. (Effectively, the average cost for the first 1000 days is the same as if the water heater had not been replaced.)

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21 points!!
Bogdan [553]

Answer:

See attached pictures.

Step-by-step explanation:

The sine and cosine functions have the forms: f(x) = C+ A sinBx and f(x) = C + A cosBx. A is the amplitude for each function. The period is found by dividing 2π the absolute value of B or \frac{2\pi}{|B|}. C shifts the function up and down.

The sine function always starts and ends on the x-axis.

The cosine function always starts and ends at the y=A.

6.) The sine function starts at (0,0) then peaks at 5. Comes down to 0 and down to -5 before returning to 0.

The amplitude is 5.

The period is \frac{2\pi}{|2|}=\pi

7.) Here A=3 so the amplitude is 3, B is 1/2 so the period is 4π. Start at (3,0) and descend down to (2π, 0). Go back up to (4π, 3).

8.) Here A = 2 so the amplitude is A. B is 2π so the period is 1. C is 1 so the graph is shifted up a unit.

Start the graph at (0,1) and go up to (0.25,3) and down to (0.5,1) and continue downward to (0.75, -3) then back up to (1,1).

3 0
3 years ago
SOLVE QUICK PLEASE!! 20 POINTS
PolarNik [594]

Answer:

SA = 384 in²

Step-by-step explanation:

Assuming we're finding surface area:

SA of top of large cube: 8(8) - 4(4) = 48 in²

SA of sides of large cube: 4(8)(8) = 256 in²

SA of exposed faces of small cube: 5(4)(4) = 80 in²

Total = 48 + 256 + 80 = 384 = ∑SA

6 0
3 years ago
G(x)=15x-10 inverse function with steps please​
Alexus [3.1K]

Answer:

The inverse function is g(x) = 

\frac{x + 10}{15}

Step-by-step explanation:

You can find the inverse of any function by switching the g(x) value (or whatever the function value is labelled) and the x value. Then solve for the new g(x) value. The result will be your inverse function.

g(x) = 15x - 10 ---> Switch the g(x) and x

x = 15g(x) - 10 ---> Add 10 to both sides

x + 10 = 15g(x) ----> Divide both sides by 15.

\frac{x + 10}{15} = g(x) ----> Switch the order

= g(x) ----> Switch the order

g(x) =

\frac{x + 10}{15}

And that would be your inverse function.

4 0
4 years ago
Math<br><br><br> is my answer correct??<br><br><br> pls check!
Luba_88 [7]

Answer:

Domain: (-2 , 3]

Range: [-3, 2)

Step-by-step explanation:

Domain is all the x's on the graph. (If you have an equation, then it's all the numbers that are allowed to be x)

Range is all the y's on the graph (or if you have an equation, all the possible y outcomes)

Open dot endpoint means that point is not included in the set (domain and range are sets of numbers) Closed dot means the point is included.

You didn't get this math question right. But look for all the x's for the domain, and all the y's for the range.

6 0
2 years ago
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Which is not a solution of sin 20 = 1?<br> A = 90<br> B = 45<br> C = 225<br> D = - 135
koban [17]
If you plug in 90 into theta, the expression becomes sin(180), which has a value of zero. Therefore 90 cannot be a solution to this equation. Hope this helps.
6 0
2 years ago
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